User talk:JRSpriggs/Archive 5

This is the file "User talk:JRSpriggs/Archive 5" which archives User talk:JRSpriggs.

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Political content on user page

Hi, I think a lot of the content on your user page is interesting, but it sits uneasily with the guidelines at WP:UPNOT. It strikes me that this material would be better posted on your personal blog (if you have one). There's probably no harm in keeping things as they are, but I'm curious about your motivations, I hope you don't mind me asking. Cheers, Jowa fan (talk) 08:01, 9 July 2011 (UTC)

I do not have a blog. In fact, I have only three active accounts on-line: (1) an e-mail account, (2) this account at Wikipedia, and (3) an account at youtube (just for watching videos, not posting them). So this is my only outlet for expressing my opinions. I cannot afford to pay for anything, so I only use these free accounts. And as a older person, I prefer not to get involved in the complexity of additional accounts, if I can avoid it.

For a long time, I did not have a user page except as a redirect to this talk page. However, I finally decided to reveal some basic facts about myself without getting into information which could be used to steal my identity or embarrass me. Talking about my interests naturally led to describing my political views which are not mainstream. Especially, when we had the financial crisis, I felt compelled to say what I thought the cause was and possible cure might be. I guess you could say it evolved into a blog, but I do not change it very often and its length is not especially great. I do sometimes remove material which no longer reflects my view or has become irrelevant to current affairs. JRSpriggs (talk) 08:25, 9 July 2011 (UTC)

Thanks for the explanation, this all makes good sense. Nowadays there are plenty of sites where one can start a blog without paying anything—but you're quite right, looking after multiple accounts can get complicated. Jowa fan (talk) 10:26, 9 July 2011 (UTC)

I agree in part with User:Jowa fan. I don't care what you have on your talk page, but I'd be concerned that Wikipedia authors could delete my stuff at any time as per WP:UPNOT: user pages are not permitted to contain extensive personal opinion or soapboxing unrelated to the Wikipedia itself. You might look into LiveJournal which is free and easy to use (and you can include a lot on your user page there if you prefer having a home-base for opinion rather than a blog), or Google Plus for a more interactive experience. WordPress is another common resource (but I'm less familiar with them personally). I hope it never becomes an issue for you, but I'd keep everything backed up either way, just to be safe. TricksterWolf (talk) 05:40, 1 September 2011 (UTC)

I do keep a local copy of the source of my user page. But it is not clear that that would be very helpful if there was a determined attack on my privilege of choosing the content of my user page. Thanks for suggesting alternative hosts, but I would rather not use them if I do not have to.

By the way, if you want people to refer to you as "she" rather than "he", you should indicate on your user page that you are a woman. For example, although I have not chosen to use userboxes myself, you could put {{User:UBX/female}}, {{User:UBX/female2}} or {{User:UBX/female3}} on your user page. JRSpriggs (talk) 08:24, 1 September 2011 (UTC)

Sure. I'll do that eventually. It's a bit odd for me, because I made this account under my pseudonym rather than my real name so that I can edit articles of a less-scholastic nature without being tracked. So far I haven't really had the need to share much personal information, but you're right that a little would help. Either way, I wasn't remotely offended, and I'm a transsexual woman so I suppose some people wouldn't consider me female anyway (though people who meet me seem to universally assume I am, fortunately).

Good to see your involvement, and thanks for pointing me to the Wikiproject page for the discussion on limit ordinal terminology. I'm still learning, and it helps. TricksterWolf (talk) 19:35, 1 September 2011 (UTC)

For other user boxes see Wikipedia:Userboxes/Gallery. JRSpriggs (talk) 03:08, 2 September 2011 (UTC)

Apology

I recently had reason to read through my talk archives, and now with the distance of time, I can see that I have sometimes been peevish and short with you during our disagreements. I wanted to apologize for that. In fact, taken as a whole, you have been remarkably patient with me. For that, my thanks.

On another matter, at one point in our discussion, we discussed evidence-based economics. I'd like to note that low inflation continues, just as New Keynesian models predict (acceleration in inflation rate is negatively related to unemployment). As such, I remain staunch in my belief in textbook macroeconomics.

regards, --LK (talk) 09:03, 21 July 2011 (UTC)

Thank you for being concerned about my feelings and apologizing. Actually, I think that few people who disagree with me so strongly would have been as patient as you have.

Perhaps you are correct that high unemployment will prevent inflation. However, we need to allow businesses to become more profitable to get the economic expansion that will reduce unemployment. This means that government must focus on reducing the burdens it puts on businesses by: (1) reducing taxes, (2) reducing regulations, and [yes] (3) reducing spending which removes inputs from the private sector thereby raising the costs of business. JRSpriggs (talk) 21:34, 21 July 2011 (UTC)

Let me add another apology / thank you. You are right, of course, to undo my FRW edit. That was a sloppy editing mistake by me; thanks for catching it! Law of Entropy (talk) 19:08, 12 May 2012 (UTC)

United States debt-ceiling crisis article: August 15 in Timeline

Please read and comment on the section "Moving the August 15 timeline entry" in the "United States debt-ceiling crisis" talk page. Thanks. --RoyGoldsmith (talk) 11:08, 12 August 2011 (UTC)

Why did you undo my edit on the metric tensor?

The insert is correct, you can find it in most textbooks (see for example, Rindler) so what qualifies it as "unhelpful"? — Preceding unsigned comment added by Czyx (talk • contribs) 04:35, 3 October 2011 (UTC)

User page, again

I see that there have been a few previous complaints about your user page. However it is still a 7,000-political manifesto. A few hundred words would be one thing, but this is out of proportion. Could you edit it down to a brief summary?   Will Beback  talk  01:44, 5 October 2011 (UTC)

Why?

Out of proportion to what? The edits I have devoted to it are only a tiny proportion of my total edits.

I could summarize my position by saying that I believe in freedom, but then no one would know what I meant, or rather they would jump to incorrect conclusions about what I believe.

Is it not said that Wikipedia is uncensored? And is my user page not intended to represent me to those who want to learn about me? Anyone who is uninterested in my ideas is free to ignore it. JRSpriggs (talk) 07:22, 5 October 2011 (UTC)

It is out of proportion to any reasonable used of a user page. Have you read Wikipedia:User pages? Pages like yours are routinely deleted.   Will Beback  talk  07:31, 5 October 2011 (UTC)

I reduced it by more than half. I really do not want to reduce it any further. JRSpriggs (talk) 12:01, 5 October 2011 (UTC)

Thanks, I appreciate the good faith effort. It's still about six times too long, but I won't pursue it further.   Will Beback  talk  20:45, 5 October 2011 (UTC)

Speedy deletion nomination of Western Republican Leadership Conference

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MfD nomination of User:JRSpriggs

User:JRSpriggs, a page you substantially contributed to, has been nominated for deletion. Your opinions on the matter are welcome; please participate in the discussion by adding your comments at Wikipedia:Miscellany for deletion/User:JRSpriggs and please be sure to sign your comments with four tildes (~~~~). You are free to edit the content of User:JRSpriggs during the discussion but should not remove the miscellany for deletion template from the top of the page; such a removal will not end the deletion discussion. Thank you.

Nom Comments: Sorry to have to do this, but it seems to have become a pervasive issue and it needs to be resolved.WaltCip (talk) 17:40, 14 October 2011 (UTC)

The discussion was closed as speedy keep: nomination withdrawn. Jowa fan (talk) 00:46, 16 October 2011 (UTC)

You may or may not be interested, but all of the parts of your manifesto that are relevant to me (e.g. not the parts concerning political / economic / social conditions in the US about which I know little) I completely agree with, in particular your miscellaneous bits at the end. Thought I'd mention it because I have found it can be good to feel that one is not alone in one's views. --Matt Westwood 20:33, 26 October 2011 (UTC)

My thanks to Matt Westwood and to all those who supported me at the MfD. JRSpriggs (talk) 06:05, 27 October 2011 (UTC)

Comsumer

Thanks for that. It was simply a type on my part. Will be fixed in the next few minutes. --User:Woohookitty ^{Disamming fool!} 17:32, 26 October 2011 (UTC)

No problem. Sometimes I forgot to read what I actually type. :) --User:Woohookitty ^{Disamming fool!} 09:28, 27 October 2011 (UTC)

Thanks

Thanks for this,[1] I appreciate it. LK (talk) 14:04, 27 October 2011 (UTC)

It'll be pleasure to buy you a drink if we ever get a chance to meet. LK (talk) 14:06, 27 October 2011 (UTC)

You are welcome. As I said above in a different context, user pages are to represent that particular user, not someone else. JRSpriggs (talk) 04:55, 28 October 2011 (UTC)

Bit puzzled

Hi JRSpriggs, I'm a bit puzzled about the purpose of this edit in response to my last reply at User talk:Sugdub. Did you perhaps somehow misplace this? Cheers - DVdm (talk) 11:23, 7 December 2011 (UTC)

I am sorry that I did not make it clear that it was addressed to Sugdub rather than to you. I just occurred to me that perhaps he would benefit from seeing a spacetime diagram of how length is measured for a moving object and that was the only one I could find on the commons. JRSpriggs (talk) 17:23, 7 December 2011 (UTC)

Ah... a piece of the puzzle :-) Ok, Cheers - DVdm (talk) 17:30, 7 December 2011 (UTC)

2 vs 3 digits

Hi JRSpriggs, I did a diff and did not see your comment before I re-inserted my correction to two digits on Methods of computing square roots. I thought it was a vandal edit. I am an engineer, so i'm used to significant digits, but i see you are a mathematician. Can you please explain or send me to a link on the 'ok if last digit off' part? Thanks Arosa (talk) 01:44, 20 December 2011 (UTC)

I can understand your desire to round off to the nearest digit, but that is not possible in general. For example, if x is only known to be between 3.3 and 3.6, then x could be described as "3 to one digit" or "4 to one digit" with equal validity. The best one can do as a consistent practice is to round to one of the two closest digits. And consider 3.48, if it is rounded to two digits, then it becomes 3.5. And then 3.5 is usually rounded to 4 (the even digit of {3, 4}) to one digit. However by your rule, rounding from 3.48 to 4 to one digit would be unacceptable.

And practically, the rule I use allows one to preserve more information than your rule allows in the case which appeared in the article. JRSpriggs (talk) 17:46, 20 December 2011 (UTC)

Indeed there are many problems with any of these approaches (including multiple roundings, the fact that 3 to 1 digit and 4 to 1 digit have zero overlap, etc). I think what you last wrote (decimal expansion starts with...) does preserve the most information. Good job. Arosa (talk) 16:49, 21 December 2011 (UTC)

The compromise you mentioned (re decimal expansion) was not my work. It was put in by Isheden (talk · contribs). I advise you to follow my practice and always read the new entries in the revision history carefully before editing. JRSpriggs (talk) 02:05, 22 December 2011 (UTC)

Spelling corrections

JRSpriggs, you made some spelling corrections on Talk:Schrödinger equation. While I share your irritation with bad spelling, it's not generally recommended that you edit comments by others (see WP:TPO). RockMagnetist (talk) 01:38, 3 January 2012 (UTC)

Disambiguation link notification

Hi. When you recently edited ICARUS (experiment), you added a link pointing to the disambiguation page Instrument (check to confirm | fix with Dab solver). Such links are almost always unintended, since a disambiguation page is merely a list of "Did you mean..." article titles. Read the FAQ • Join us at the DPL WikiProject.

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Thanks for pointing that out. I have disambiguated the link. JRSpriggs (talk) 09:18, 27 February 2012 (UTC)

Addison not Addision of course

I was responsible for the misspelling (which you will not be surprised by), and have now corrected its origin

"Quantum Mechanics, E. Abers, Pearson Ed., Addision Wesley, Prentice Hall Inc, 2004, ISBN 9780131461000

to

"Quantum Mechanics, E. Abers, Pearson Ed., Addison Wesley, Prentice Hall Inc, 2004, ISBN 9780131461000

on my own user page in the references section. I haven’t been using WP much recently so didn't notice your post at wikiproject physics here a few days ago.

Sorry to waste so much of yours (and whoever made the corrections) time... =( F = q(E+v×B) ⇄ ∑_ic_i 16:06, 25 March 2012 (UTC)

Main page appearance: General relativity

This is a note to let the main editors of General relativity know that the article will be appearing as today's featured article on April 19, 2012. You can view the TFA blurb at Wikipedia:Today's featured article/April 19, 2012. If you prefer that the article appear as TFA on a different date, or not at all, please ask featured article director Raul654 (talk · contribs) or his delegate Dabomb87 (talk · contribs), or start a discussion at Wikipedia talk:Today's featured article/requests. If the previous blurb needs tweaking, you might change it—following the instructions at Wikipedia:Today's featured article/requests/instructions. If this article needs any attention or maintenance, it would be preferable if that could be done before its appearance on the Main Page. The blurb as it stands now is below:

General relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics. General relativity generalises special relativity and Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time. In particular, the curvature of spacetime is directly related to the four-momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations. Some predictions of general relativity differ significantly from those of classical physics. Examples of such differences include gravitational time dilation, gravitational lensing, the gravitational redshift of light, and the gravitational time delay. General relativity's predictions have been confirmed in all observations and experiments to date. Although general relativity is not the only relativistic theory of gravity, it is the simplest theory that is consistent with experimental data. However, unanswered questions remain, the most fundamental being how general relativity can be reconciled with the laws of quantum physics to produce a complete and self-consistent theory of quantum gravity. (more...)

UcuchaBot (talk) 23:01, 17 April 2012 (UTC)

RE: Failure of protection

Hi. I only enabled move proection. Hope this answers your question. Rjd0060 (talk) 20:03, 19 April 2012 (UTC)

Thank you for clarifying that. I had been under the impression that the featured article of the day was normally given at least protection against IP-users and new users, i.e. semi-protection. I have now been informed that that is not the policy. Still, I feel that it should be the policy. JRSpriggs (talk) 21:11, 19 April 2012 (UTC)

Conjugate Variables: Derivation from Action

Hi JR, thank you for your edits. Can you expand your edit for conjugate variables, you've edited that "the derivatives of action are conjugate variables to the quantity with respect to which one is differentiating", but there's no reference for this or elaboration of how it's down.

Also, your units don't make sense, they way you have presented indicates that all conjugated variables in physics are governed by Planck's constant, however, plugging the units in for potential and charge density [J Q^-1][Q L^-3] I get [M L^-1 T^-2] which is close to [h] = [M L^2 T^-1] but not. Could you explain in more detail your reasoning? — Preceding unsigned comment added by Larsobrien (talk • contribs) 02:10, 21 April 2012 (UTC)

your's sincerely - Lars — Preceding unsigned comment added by Larsobrien (talk • contribs) 00:06, 21 April 2012 (UTC)

The last equation in the section Covariant formulation of classical electromagnetism#Lagrangian for classical electrodynamics says that the Lagrangian density of the electromagnetic field is

${\mathcal {L}}\,=\,{\frac {1}{2}}(\epsilon _{0}E^{2}-{\frac {1}{\mu _{0}}}B^{2})-\phi \,\rho _{\text{free}}+{\boldsymbol {A}}\cdot {\boldsymbol {J}}_{\text{free}}+{\boldsymbol {E}}\cdot {\boldsymbol {P}}+{\boldsymbol {B}}\cdot {\boldsymbol {M}}\,$

while the action is

$S=\int {\mathcal {L}}\,dxdydzdt\,.$

Strictly speaking, varying a variable at one point will not affect the integral. To change the integral, one must make the variation over a hyper-volume of space-time

$\Delta x\Delta y\Delta z\Delta t\,$

which has units [L^3 T]. So we need to differentiate the action with respect to the charge density within a unit hyper-volume in order to get the electric potential. Thus take [M L^-1 T^-2] and multiply it by [L^3 T] which gives the desired [M L^2 T^-1]. A similar thing must be done with the other conjugate pairs in field theory. JRSpriggs (talk) 07:34, 21 April 2012 (UTC)

On second thought, what I was saying was nonsense. Instead of relying on my error-prone memory, I need to look this up in a text book and get back to you. JRSpriggs (talk) 04:57, 24 April 2012 (UTC)

I have not been able to find it in my textbooks. But on further thought, I believe that there is no conjugate variable for the electric scalar potential, φ; and the conjugate variable for the electromagnetic vector potential, A, is the negative of the electric displacement, −D. Similarly, there is no conjugate variable for the Newtonian gravitational scalar potential. In this case, the units of the product −A·D should be the same as action divided by a unit (3-)volume.

When you apply the calculus of variations to derive the Euler-Lagrange equations from the principle of least action, there usually are terms which come from integration by parts and take form of integrals over the 3-dimensional boundary of the 4-dimensional hyper-volume over which you are integrating the variation in the Lagrangian density. The conjugate variables are found from those boundary terms. For example in this case, the boundary integral's integrand is −D·δA. JRSpriggs (talk) 19:05, 26 April 2012 (UTC)

Dear JR,

Is it possible you are confusing intensive and extensive variables in Thermodynamics with the symplectic vector spaces of the Heisenberg group?

The conjugate variables in the Heisenberg uncertainty relation are related through their Fourier transform duals, whereas the conjugate variables in thermodynamic properties are related through Maxwell relations which are taken as derivatives of thermodynamic potentials.

After some thought I see where you're coming from, and how taking derivatives of the Lagrangian gives conjugate pairs, c.f. Canonical commutation relation, and your approach makes a lot of sense.

It's a pity V and φ aren't conjugate, I really could have done something useful with that.

Despite all that, I think you should continue with your edit, hopefully you can show V and φ are Fourier transform duals.

your's sincerely - Lars — Preceding unsigned comment added by Larsobrien (talk • contribs) 00:14, 27 April 2012 (UTC)

As you indicate, there is a notion of conjugate variables in thermodynamics, but that is distinct from the notion of conjugate variables in mechanics which is what I was addressing. There is a separate article on conjugate variables in thermodynamics.

Could you clarify what you mean by V and φ? If you mean voltage and the electric scalar potential, they are the same thing (only the name is changed). JRSpriggs (talk) 12:03, 28 April 2012 (UTC)

Ricci calculus

Hi, this article is awesome, the first time I have seen such a complete and transparent summary for this concept.

		The Teamwork Barnstar
		This is to be shared between: F=q(E+v^B) - the original author, LutzL - historical content, accuracy and sources, Quondum, JRSpriggs, TimothyRias - corrections and mathematical accuracy, clean up, clarification etc. Maschen (talk) 16:32, 20 May 2012 (UTC)

Well done and thanks to you all, and sorry this is so late (I would have awarded this earlier but don't get on WP much anymore). Best, Maschen (talk) 16:32, 20 May 2012 (UTC)

You are welcome. JRSpriggs (talk) 21:11, 20 May 2012 (UTC)

Was that all?

You could have disagreed with my summary of the source without accusing me of editing under false pretenses, you know. I pared down that bullet point a bit, see if you still like it: https://en.wikipedia.org/w/index.php?title=United_States_debt-ceiling_crisis&diff=495617632&oldid=495606587. We can move to the article's talk page if you think there is anything else we need to take care of. FiveColourMap (talk) 13:43, 2 June 2012 (UTC)

I did not mean to imply that you were intentionally doing anything wrong. I merely meant that your edit was one-sided.

This is a difficult issue to address since how one describes the situation has implications for who (Republicans or Democrats) gets the blame. And it may be hard for a reader to separate what S&P is saying (which is deliberately vague to avoid offending one party or the other) from what Wikipedia is saying. JRSpriggs (talk) 03:31, 3 June 2012 (UTC)

I did not mean to imply that you were intentionally doing anything wrong. - thank you. Happy Sunday! FiveColourMap (talk) 19:17, 3 June 2012 (UTC)

I hope you check you recent assertions

A tensor basis of a given type can be expressed as the tensor product of possibly different sets of vector bases. This is mathematically sensible; if your thinking becomes too component-centric rather than being in terms of the actual (abstract) tensors, you can lose sight of this. Your recent edit comment about the Kronecker delta and Lorentz transform shows up the difference in our perspectives. I do not intend to argue this with you. — Quondum^☏ 11:20, 19 June 2012 (UTC)

Some things may be tensors in a mathematical sense which are not tensors in the sense of general relativity physics. Just as one might say that any space of tensors is a vector space in a mathematical sense, but not in a physical sense. In physics, we are focusing on particular mathematical objects which are useful in modeling reality, not just on anything that someone can imagine. JRSpriggs (talk) 07:09, 20 June 2012 (UTC)

Intolerable behaviour by new user:Hublolly

Hello. This message is being sent to inform you that there is currently a discussion at WP:ANI regarding the intolerable behaviour by new user:Hublolly. The thread is Intolerable behaviour by new user:Hublolly. Thank you.

(I had to include you by WP:ANI guidelines, sorry...)

F = q(E+v×B)⇄ ∑_ic_i 23:06, 9 July 2012 (UTC)

Thank you for letting me know about that thread. JRSpriggs (talk) 03:25, 10 July 2012 (UTC)

Fuckscrew that - instead please desist from whipping up so much opposition. I apologized already. Why block?? Hublolly (talk) 12:06, 10 July 2012 (UTC)

Re: Thanks for fixing the units at GEM

Hi, in regards to your message on Gravitoelectromagnetism, considering you wrote the equations, I was wondering if you'd consider putting Maxwell's Equations into Gaussian (CGS) units. The parallels are clearer and theoretical physicists (especially those who would work in GEM) prefer Gaussian for E&M anyway (even if the "new" Jackson uses SI now). I'd want to clear it with you first, though. SamuelRiv (talk) 19:38, 6 August 2012 (UTC)

Re: Dated parameter

I replied at User_talk:Magioladitis#Removing_date_paramters. I think you misunderstood the problem. Dated parameters are fine as soon as the tag supports them. The problem is dated parameters on stub tags which don't support it. -- Magioladitis (talk) 07:03, 9 August 2012 (UTC)

wave function

I believe the thing you are thinking of comes from the partition function (quantum field theory) -- see equation there. The S in that equation is the action (physics) -- pick your favorite action. (they also seem to have set hbar=1 in that article, which makes expanding in powers of hbar difficult :-() With appropriate derivatives and limits and manipulations and hand-waving, you can get a result similar to what you mentioned. This is because the integrand with the exp(iS) can be thought of as a Gaussian, whose peak is located exactly at the classical action (by method of steepest descent aka stationary phase approximation). However, Gaussians in these kinds of infinite-dimensional systems have surprising behavior. My most recent head-scratcher/aha moment is for the asymptotic equipartition property which is the probability-theory version of the above. linas (talk) 05:27, 18 August 2012 (UTC)

I am sorry, but that went over my head.

In Momentum operator, it attempts to use the de Broglie relations to justify the identification of linear momentum as

${\hat {p}}\Psi =-i\hbar {\frac {\partial \Psi }{\partial x}}\,,$

but this is not entirely convincing. I thought that using

$p={\frac {\partial S}{\partial x}}\,$

where S is Hamilton's principal function would help to justify this which it would if (as I had thought)

$\Psi \approx A\exp {\frac {iS}{\hbar }}\,$

when you are nearly on-shell, so that

${\frac {\partial \Psi }{\partial x}}\approx {\frac {i}{\hbar }}{\frac {\partial S}{\partial x}}\Psi ={\frac {i}{\hbar }}p\Psi \,.$

In all this I was thinking of the quantum mechanics of one particle, not quantum field theory. JRSpriggs (talk) 03:34, 19 August 2012 (UTC)

Infinite

Please read the disambiguation guidelines, particularly WP:PTM. Infinity has its own dab page, and infinite set is not synonymous with infinite. Clarityfiend (talk) 20:29, 23 August 2012 (UTC)

The relevant question is, "What would a person who ended up at the page titled "infinite" be looking for?" And the answer is that such a person would almost certainly be looking for an article about mathematics, probably the article Infinity. Both the MOS and the dab guidelines in particular are clear that primary meanings should come first. The fact that these are also partial title matches is irrelevant. --JBL (talk) 21:47, 23 August 2012 (UTC) (now copied to talk page)

AC and Group Structure

Hi!

I have written a proposal for a new article. It's about the equivalence of AC and the existence of a group structure on every set. It's on my talk page. (It's about the only thing there, so you'll be able to locate it. Lead + two sections + references) I'd like to place it in the AC category if it's good enough, and perhaps link it from the AC article. Perhaps it should be in category Group too.

I think that the first section (Group Structure -> AC) is kind of neat. Well, perhaps not my presentation of it, but the main reasoning, which I think come from the second reference.

I'd be happy if you, Carl and Trovatore (and anybody else you feel ought to) could have a look at it. It's not in mint condition yet, but I don't want to spend too many more hours on it in case you all say booooooo. Keep in mind that I am just a layman.

Best Regards, Johan NystromYohanN7 (talk) 12:37, 15 September 2012 (UTC)

A kitten for you!

````

Xh286286 (talk) 03:53, 17 September 2012 (UTC)

Thank you for the kitten. I am glad that I was able to answer your question at Talk:General relativity#I think the simulated black hole image is not correct. JRSpriggs (talk) 05:36, 17 September 2012 (UTC)

Help with peer review?

Hi James; remembering your helpful contributions back when general relativity was on its way to FA status, could you possibly help with the peer review of Jürgen Ehlers? I've put the article up for peer review here. Thanks in advance, and all the best, Markus Poessel (talk) 19:41, 2 October 2012 (UTC)

I am not familiar with the work of Jürgen Ehlers, so I doubt that I could help much. I read the article and nothing seemed "off" to me. JRSpriggs (talk) 06:34, 3 October 2012 (UTC)

List of large cardinal properties

There is a problem. You undid my edition of interwiki. The reason was that if you will go to Czech version there will be interwiki back to English on page Large cardinal. And in Czech Velké kardinály means Large Cardinals. So there is an interwiki conflict Divega (talk) 06:36, 24 October 2012 (UTC)

The main content of the Czech article, cs:Velké kardinály, appears to be a list of large cardinal properties. Thus if any change is necessary, it should be a renaming of the Czech article. JRSpriggs (talk) 08:27, 24 October 2012 (UTC)

First part is a definition of what is Large Cardinals, second - Historie (history), third - relation of cardinals and fourth contains the list of cardinals ("Seznam" means list). So at the moment interwiki isn't correct and should be deleted. --Divega (talk) 08:47, 24 October 2012 (UTC)

I disagree. There is no good reason why one cannot link both Large cardinal and List of large cardinal properties to the same Czech article, if it covers both topics as it appears to do.

It may confuse some simplistic computer programs, but it is not problem for the readers which is what matters. JRSpriggs (talk) 08:55, 24 October 2012 (UTC)

(ec) So what that means is that both English articles should link to the Czech article, and the Czech article should link to both of them. Unfortunately that's too complicated for the bots. It's the kind of thing Jim Kirk would have done to them to make them blow up. We need a way to turn the bots off in this sort of circumstance. --Trovatore (talk) 08:56, 24 October 2012 (UTC)

Perhaps the bots should merely point out potential problems and have them reviewed by a human, rather than trying to fix everything completely automatically. Or are they already doing that, and the problem is that the humans are too lazy busy to deal with it? JRSpriggs (talk) 09:07, 24 October 2012 (UTC)

ZFC page

I see you reverted my edits from what appears to be one mistake I made concerning Kunen. However, I think the changes I made beneficial for two reasons: (i) they corrected some errors and made some small clarifications, (ii) they made beneficial stylistic changes.

Regarding (i). In line 16, the omission of the "set existence" axiom of Kunen has nothing to do with mathematicians and first-order logic ignoring an empty domain. Indeed, the axiom ensures that any model of the theory have an inhabited domain. The part "as it begins with an existential quantifier" is not helpful for the intended audience.

Line 45 was edited for stylistic reasons. E.g. the parenthetical remark "see above" is unhelpful. See where exactly? The "can be used to prove" talk is unattractive.

In line 76 it is implied that the axiom of infinity literally says that there is a set having infinitely many members. Not true. That is a consequence of the axiom. Furthermore, a constant for the empty set figures in it, but it is later stated that the existence of the empty set is provable from the axiom of infinity. Obviously this doesn't work.

If you wish to be the wiki police on ZFC, please look at the edits more carefully before doing a "mass revert". True, my reverts were not critical, but I think they do make a small improvement (save the mis-edit about Kunen).

Best, Nort — Preceding unsigned comment added by Nortexoid (talk • contribs) 21:25, 24 October 2012 (UTC)

I will reply at Talk:Zermelo–Fraenkel set theory. JRSpriggs (talk) 04:44, 26 October 2012 (UTC)

Klein-Gordon

After consultation with other textbooks, it was determined that there is an error in Principles of Quantum Mechanics by Shankar that we did not see on page 576. Thank you for your corrections on the page and informing us to look harder. — Preceding unsigned comment added by 129.97.124.72 (talk) 18:56, 10 December 2012 (UTC)

You are welcome. JRSpriggs (talk) 05:13, 11 December 2012 (UTC)

Contradiction

On your user page, under the heading “Non-contradiction,” you wrote that “Contradictions do not exist in reality.” Contradictions are linguistic and therefore always related to language. As words, they exist as real discursive thoughts or real verbal expressions. They do not, however, exist as real, actual spatial and temporal objects.Lestrade (talk) 21:12, 21 December 2012 (UTC)Lestrade

If a contradiction appears in your use of language, then you have abused the language in some way. This should not be ignored, but fixed.

Are you claiming that language should not be taken seriously? JRSpriggs (talk) 08:24, 22 December 2012 (UTC)

No, merely that a contradiction is very real as either a verbal thought, written word, or spoken word. It is not real in any other mode of reality.Lestrade (talk) 11:33, 22 December 2012 (UTC)Lestrade

Are you agreeing with what I said on my user page or disagreeing?

If agreeing, then why did you mention it in this way?

If disagreeing, then please state what you find wrong with it more clearly. JRSpriggs (talk) 12:41, 22 December 2012 (UTC)

I disagreed with you and tried to explain my disagreement in the following way: On your user page, under the heading "Non-contradiction," you wrote that "Contradictions do not exist in reality." But, a contradiction is very real as a verbal thought, written word, or spoken word. However, being language, a contradiction is not real in any non–verbal way. Lestrade (talk) 10:32, 26 December 2012 (UTC)Lestrade

If I said that unicorns do not exist, I hope that you would not think that I was denying the existence of the word "unicorn" nor the existence of an idea of what a unicorn would be. Rather I would be saying that the word has no referent and there is no existent which satisfies the criteria for being a unicorn.

Similarly, if I said that "The pope is a bear; but the pope is not a bear." is an example of a contradiction which does not exist in reality, you should not think that I am denying the existence of that sentence nor of the criteria which the pope would have to satisfy to both be a bear and not be a bear. Rather I am saying that the solution set for these criteria is empty.

A contradiction like that is not true in any possible world and certainly not in this world.

Thus a (finite) sequence of propositions which purports to prove such a contradiction must contain a first fallacious step, that is, a step which is false even though the steps from which it purports to follow (if any) are true. I am saying that it is important for your intellectual integrity to identify that step so that you do not make a similar mistake in the future.

Is it clear now? JRSpriggs (talk) 07:07, 27 December 2012 (UTC)

Yes. My opinion is that contradictions exist only in an abstract, discursive, verbal, linguistic, logical, dialectical state. They do not exist in a concrete, sensuous, perceptive, empirical, intuitive, actual state. To me, the distinction between conceptual words and perceived objects is important. Thinkers such as Spinoza, Hegel, and Marx mistook them and based their thinking on the resulting confusion. Hegel went so far as to claim that verbal notions move like physical objects.Lestrade (talk) 20:40, 27 December 2012 (UTC)Lestrade

So do you now accept what I said at User:JRSpriggs#Non-contradiction as it stands? Or would you like to suggest a revised wording? JRSpriggs (talk) 07:19, 28 December 2012 (UTC)

Review

Hi!

How are you? Hope fine... I wanted to discuss with you the problem going on in the section Lists of integrals#Absolute value functions. I am the user who had put up the recently removed formulae for |sin| and |cos|. The formulae were slightly incorrect due to my use of the sgn function. The formulae you entered seem to be O.K., but are no simpler than mine. I have resolved the problem with the sgn function in my old formulae. They are here. Can you consider replacing yours with these?

$\int \left|\sin {ax}\right|\,dx={4 \over a}\left\lceil {\frac {ax-\pi }{2\pi }}\right\rceil -{1 \over a}\operatorname {sgn} \left(\operatorname {sgn}(\sin {ax})+{1 \over 2}\right)(\cos {ax}-1)+C\;$

$\int \left|\cos {ax}\right|\,dx={2 \over a}\left\lceil {\frac {2ax-\pi }{2\pi }}\right\rceil +{1 \over a}\operatorname {sgn} \left(\operatorname {sgn}(\cos {ax})+{1 \over 2}\right)\sin {ax}+C\;$

Hope you accede to my request.

—Sγεd Шαмɪq Aнмεd Hαsнмɪ (тαʟк) 18:48, 10 April 2013 (UTC)

If you have a reference to support your version (which I do not have for mine), then that would be a good reason to replace my version with yours. In any case, you are free to do as you please. However, I still think that your version is harder to understand than mine. JRSpriggs (talk) 20:23, 10 April 2013 (UTC)

No problem... Let them be there as you wish!

—Sγεd Шαмɪq Aнмεd Hαsнмɪ (тαʟк) 07:00, 11 April 2013 (UTC)

Derivatives of Inverse trigonometric functions

Hi! This is Wamiq again... I added the domains for the derivatives of the inverse trigonometric functions in the section, which you have recently removed (Sorry for bothering you ☹). Thanks for pointing out that those derivatives encompassed complex numbers as well, but would it not have been a good idea to keep the domains after modifying them by excluding the values at which the functions were undefined even in the complex plane? I think that their domains in the complex plane should be added into that section. What do you think? I hope you agree to putting up new domains... Regards,

— Syεd Шαмiq Aнмεd Hαsнмi (тαlк) 21:24, 13 April 2013 (UTC)

I usually prefer to discuss things on the talk page of the article in question. So I will respond at Talk:Inverse trigonometric functions. JRSpriggs (talk) 15:13, 14 April 2013 (UTC)

Notation

Thanks a lot! That section looks better now ☺. Well, I see an issue with the notation used on Wikipedia for the inverse trigonometric functions, i.e., the convention here is to denote all functions with minuscule letters but to add the word arc with the inverse ones (sin x, arcsin x, etc...) but what we (along with our textbooks) do, is to denote regular functions with minuscule letters, e.g., sin x, cos x, etc., and the inverse functions with the first letter majuscule and a −1 superscript, e.g., Sin<sup>−1</sup> x, Cos<sup>−1</sup> x, etc., which causes no confusion between the inverse function (Sin<sup>−1</sup> x) and the multiplicative inverse (sin<sup>−1</sup> x). This notation is nowhere to be found here. I personally find the arc notation a bit odd. Do you find this (capital) notation at least worth mentioning in the article (if the arc notation is popular and cannot be removed)? Hoping to get a reply in the affirmative... Regards,

— Syɛd Шαмiq Aнмɛd Hαsнмi (тαlк) 06:26, 15 April 2013 (UTC)

Poincaré group

this goes immediately to WikiProject Mathematics. I hope to have not much future interaction with you. Incnis Mrsi (talk) 04:49, 15 April 2013 (UTC)

Disambiguation link notification for April 17

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Global Economic Map

You said: Even within the United States, there have been complaints that economic data are not defined consistently over time (from one administration to the next). How does one adjust GDP for differences in the prices of goods and services?: prices change over time, prices are different in different places, the quality of the goods or services may vary, which exchange rate should be used, surveying methods for gathering and aggregating data vary, etc.? How do you measure employment?: how many hours does a worker have to work to be considered employed, if he has multiple jobs do you count each one separately, what about the 'underground economy', how do you define the sectors (industries) of the economy for purposes of sorting workers, etc.? What about erroneous economic data due to either incompetence or politically motivated fraud (since politicians often pressure bureaucrats to change the results to create a more favorable appearance)? For more information, see shadow statistics. JRSpriggs (talk) 16:54, 14 April 2013 (UTC)

Yes people should take the data with a grain of salt but it will be the most concise and edcuational economics project available to the public. Would you be willing to help out in this endeavor?Mcnabber091 (talk) 12:06, 17 April 2013 (UTC)

I saw this when you posted it at User talk:Arthur Rubin. I am sorry, but I do not have the time to help you with your project. JRSpriggs (talk) 00:35, 18 April 2013 (UTC)

Axiom of global choice?

Hi! My name is Sergei Akbarov. I would like to invite you to the talk here http://en.wikipedia.org/wiki/Talk:Axiom_of_global_choice — Preceding unsigned comment added by Eozhik (talk • contribs) 06:40, 19 April 2013 (UTC)

Problem with complex numbers

Hi Spriggs! This is Wamiq again. I just had a small problem with complex numbers. Thought you might be of some help. Can you just point out the flaw here?

$i={\sqrt {-1}}={{\sqrt {-1}} \over 1}={{\sqrt {-1}} \over {\sqrt {1}}}={\sqrt {-1 \over 1}}={\sqrt {1 \over -1}}={{\sqrt {1}} \over {\sqrt {-1}}}={1 \over {\sqrt {-1}}}={1 \over i}=-i\ \ ??$

Both of my Maths and Physics teachers were unable to answer this. Hope you know the answer. I would be very grateful. Regards

— Syɛd Шαмiq Aнмɛd Hαsнмi (тαlк)

—Preceding undated comment added 19:12, 25 April 2013 (UTC)

Hi, Wamiq.

${\sqrt {1 \over -1}}\neq {{\sqrt {1}} \over {\sqrt {-1}}}\,.$

More generally, although

${\sqrt {a\cdot b}}={\sqrt {a}}\cdot {\sqrt {b}}\,$

holds for positive real numbers a and b, all one can conclude for complex numbers z and w is

${\sqrt {z\cdot w}}=\pm {\sqrt {z}}\cdot {\sqrt {w}}\,.$

This is because the square-root function has a branch point at zero. There are two sheets (branches) corresponding to the two roots of r<sup>2</sup>=z. If you circle around the origin (zero) once, then you end up on the other sheet. Thus when you define the square-root, it is necessary to cut the two sheets apart. Traditionally, the cut (for square-root specifically) is placed along the negative real axis. See Methods of computing square roots#Negative or complex square. If z and w both have positive imaginary parts (or are negative real) and z·w has a negative imaginary part (or is positive real), then

${\sqrt {z\cdot w}}=-{\sqrt {z}}\cdot {\sqrt {w}}\,.$

Similarly, if z and w both have negative imaginary parts (or are positive real) and z·w has a positive imaginary part (or is negative real).

Otherwise, you get the plus sign. JRSpriggs (talk) 20:03, 25 April 2013 (UTC)

Thanks a lot! I’ve got it now. So, my derivation should be something like this:

$i={\sqrt {-1}}={{\sqrt {-1}} \over 1}={{\sqrt {-1}} \over {\sqrt {1}}}={\sqrt {-1 \over 1}}={\sqrt {1 \over -1}}={-{\sqrt {1}} \over {\sqrt {-1}}}={-1 \over {\sqrt {-1}}}={-1 \over i}=i$

Thanks once again for telling me this. I am highly obliged by you. Regards...

— Syɛd Шαмiq Aнмɛd Hαsнмi (тαlк)

A cookie and thank you for fixing my mistake.

Here is a cookie for your effort in cleaning up my mess. Your diligence to stay on top of things is appreciated

.

You reverted an edit I made to Colony collapse disorder that changed the name of a wiki link. I definitely made a mistake. I must have confused which editor had actually shortened the name and this resulted in me reverting a person who fixed the problem. I was getting tired at the time and probably should have quite sooner. I am usually more careful. Thank you for fixing the mistake so promptly. It was certainly embarrassing. When I came here to leave you this message, I looked at your user page. I really like what you have written. I strongly agree with almost all of your ideas. No immigration policies is an idea that will need some thought from me. I guess, if too many people move into certain countries, the ones they leave will be forced to change to prevent continued loss of their citizens. Maybe things would eventually balance but in the meantime it could get messy. I would like to hear your thoughts about this if you are willing. I think one of the worst problems we face is too many unknowledgable voters. If we could remedy this situation, many others could be fixed. I have enjoyed "meeting" you. Probing Mind (talk) 16:23, 28 April 2013 (UTC)

You are welcome. I have made the same kind of mistake a few times, so I know how embarrassing it can be.

Thank you for your support for my user page. JRSpriggs (talk) 04:30, 29 April 2013 (UTC)

Regarding the issue of restrictions on immigration, the argument for restrictions is given by Thomas Sowell at [2] and continued at [3].

The argument against restrictions is given by Harry Binswanger at [4].

I agree with the Objectivist (and Libertarian) position as expressed by Harry Binswanger. (Warning: although many people regard Objectivists as a species of Libertarian, the Objectivists themselves violently disagree and regard Libertarians as one of their main enemies). JRSpriggs (talk) 21:43, 29 April 2013 (UTC)

Thanks for the link. A very interesting article. I think changes to welfare laws, federal and state, are a key component of making this idea work. Dealing with those who break the law also. I would be interested in anything else you run across related to the ideas on your page, if you have time and don't mind passing me a link. I'll be doing some research of my own in my spare time, short as it is. My email link should be enabled if you'd rather use email for this type of topic. A last thought, if everybody has equal access, we won't be overrun with one type of immigrant who happens to be in a position to circumvent the laws. I'd like to see us keep our melting pot mix of people. Probing Mind (talk) 11:38, 4 May 2013 (UTC)

Your revert at Tests of general relativity

Hi! You reverted my edit at Tests of general relativity. I was in a bit of a hurry and probably explained myself badly: what I meant with "Not a primary source" was that the article referenced simply cites another paper that states the value in question, so in that sense it is not the "primary source" for that value. Besides, I also removed the citation because there's a long history of cross-wiki spamming for papers from that author, and the value is already referenced anyway from another source. If you're OK with this explanation I will restore my edit. Thanks, --Snow Blizzard 18:11, 12 May 2013 (UTC)

OK. JRSpriggs (talk) 22:27, 12 May 2013 (UTC)

WikiProject Freedom of speech

Well, if you feel an article is relevant to the topic of Freedom of speech, you can add it to this WikiProject by adding {{WikiProject Freedom of speech}} to its article talk page. — Cirt (talk) 14:46, 22 May 2013 (UTC)

Invitation to join WikiProject Freedom of speech

• WP:WikiProject Freedom of speech

I've recently gone ahead and created WP:WikiProject Freedom of speech. If you're interested, here are some easy things you can do:

1. List yourself as a participant in the WikiProject, by adding your username here: Wikipedia:WikiProject_Freedom_of_speech#Participants.
2. Add userbox {{User Freedom of speech}} to your userpage, which lists you as a member of the WikiProject.
3. Tag relevant talk pages of articles and other relevant pages using {{WikiProject Freedom of speech}}.
4. Join in discussion at Wikipedia talk:WikiProject Freedom of speech.
5. Notify others you think might be interested in Freedom of speech to join the WikiProject.

Thank you for your interest in Freedom of speech, — Cirt (talk) 14:47, 22 May 2013 (UTC)

Invitation for taking a short survey about communication and efficiency of WikiProjects for my research

Hi JRSpriggs, I'm working on a project to study the running of WikiProject and possible performance measures for it. I learn from WikiProject Mathematics and Physics talk page that you are an active member of both projects. I would like to invite you to take a short survey for my study. If you are available to take our survey, could you please reply an email to me? I'm new to Wikipedia, I can't send too many emails to other editors due to anti-spam measure. Thank you very much for your time. Xiangju (talk) 15:29, 22 May 2013 (UTC)

You're too fast!

I went back to undo my wrong "correction," but you had beat me to it.  :-P — Preceding unsigned comment added by Drcooljoe (talk • contribs) 21:34, 2 June 2013 (UTC)

Others have made this same mistake before, so I did not have to think about it too much before reverting. JRSpriggs (talk) 02:10, 3 June 2013 (UTC)

Dirac equation

I have noticed that you have changed typography of the "E" at the above page in to an inelegant form. I have undone it. Please do not deface the article. — Preceding unsigned comment added by Dimension10 (talk • contribs) 14:39, 12 July 2013 (UTC)

I have looked at Dirac equation, and I have no idea what you mean. I merely reverted your reversion of Maschen's correction. The "E" near the beginning of the section Dirac equation#Hole theory (if that is what you mean) in Maschen's version is clearly more compatible with the type face of the text than the one in your version. JRSpriggs (talk) 23:55, 12 July 2013 (UTC)

Of God and religion

I have learned for myself that your beliefs are false. You have a grave misunderstanding of God and religion; my life has changed immensely for the better as I am a convert to Christianity. Do you believe I'm an idiot? 70.102.89.181 (talk) 19:06, 13 October 2013 (UTC)

I do not believe that all Christians are idiots. Some have been quite intelligent.

Do I know you? I do not recognize you from your IP address.

What evidence led you to your belief in Jesus? JRSpriggs (talk) 05:23, 14 October 2013 (UTC)

Revert in Axiom of regularity

You are right in that the empty set is not a special case, somehow my circuitry shortcut badly for a moment.

Thank you!

Jose Brox (talk) 13:18, 17 October 2013 (UTC)

You are welcome. JRSpriggs (talk) 23:57, 17 October 2013 (UTC)

Your recent question about the Obamacare article

A blog entry that is critical of Obamacare contains more than 100 reliable sources that could be used to improve wikipedia's Obamacare article. The blog was written by wikipedia User:Grundle2600, who was banned from wikipedia by Obama supporters who wanted all the Obama articles at wikipedia to be censored of any and all reliably sourced criticism.

(deleted per WP:SPAM and WP:BE)

Good question 32 (talk) 09:11, 1 November 2013 (UTC)

I cannot back out of the website you mentioned. So I had to close my browser. Such user-hostile behavior is not a good sign. JRSpriggs (talk) 22:13, 1 November 2013 (UTC)

Hi JR. I just thought you'd like to know that the user who posted this has been confirmed as a sockpuppet of Grundle2600 and has been blocked accordingly. --Dr. Fleischman (talk) 18:18, 7 November 2013 (UTC)

To DrFleischman: Thank you for letting me know about that. JRSpriggs (talk) 11:11, 8 November 2013 (UTC)

Please don't feed him

Hi, sorry to bother you here. I'm afraid this isn't too helpful. I can understand the temptation, but it goes against WP:FORUM. Usually I don't mind too much, but it encourages LCcritic, and the guy needs a larting far more than he needs discussion. Regards, Paradoctor (talk) 03:02, 24 November 2013 (UTC)

Maryland Health Benefits

Please, before you "correct" my error as creating a pretender, please fact check. If you look at the meeting minutes from Maryland Health Benefit Exchange, you'll find that http://marylandhbe.com is, in fact, a legitimate site. Naugahyde (talk) 12:59, 5 December 2013 (UTC)

Which meeting (the date), please? Or directly link to those minutes. JRSpriggs (talk) 01:12, 6 December 2013 (UTC)

I provided the link in my original comment: http://msa.maryland.gov/msa/mdmanual/25ind/html/42healben.html Naugahyde (talk) 02:29, 6 December 2013 (UTC)

OK, I see it now. I am sorry that I inconvenienced you. JRSpriggs (talk) 05:38, 6 December 2013 (UTC)

It's all good. We're just trying to improve upon Wiki.... Naugahyde (talk) 05:43, 6 December 2013 (UTC)

Thanks much

Thank you for your formatting help at Talk:Freedom of speech.

Much appreciated,

— Cirt (talk) 14:18, 20 March 2014 (UTC)

Hamiltonian mechanics

Hi!

I saw your recent revert over there. I thought about reverting it myself, but changed my mind because the edits weren't untrue to their point. Does it say anywhere in the article that the Hamiltonian doesn't always give the total energy of the system? (I don't have time to read it now.) As Mark Viking pointed out, the details can be found in Goldstein's Classical Mechanics. YohanN7 (talk) 10:58, 25 March 2014 (UTC)

Please make your argument at Talk:Hamiltonian mechanics. Give a quotation from Goldstein or otherwise present an example where the Hamiltonian is not the total energy. I do not believe that there is any such case based on my current understanding. I am aware of cases where the division of energy into: kinetic versus potential versus heat, or gravitational potential versus electrical potential versus other kinds of potential energy (elastic, chemical, etc.) is ambiguous. But that is not the same thing. JRSpriggs (talk) 07:55, 26 March 2014 (UTC)

No, I'm not going to raise an argument on the talk page because I don't have the time to get involved. Still, the reference is Goldstein, page 61 (second edition). When a velocity-dependent potential is present, then the Hamiltonian is not, in general, the total energy of the system. It may still be the total energy as a charged particle in an EM potential shows.

Goldstein presents sufficient conditions for when the Hamiltonian is the total energy. He points out that there is no reason intrinsic to mechanics that these conditions are fulfilled, but the exceptions are in practice rare. YohanN7 (talk) 10:32, 26 March 2014 (UTC)

And oh, forgot to say, I don't consider this as a big issue, which is why I don't want to get involved. Best! YohanN7 (talk) 11:02, 26 March 2014 (UTC)

Re: False assumption

Greetings,
I apologize for the misunderstanding. When I was talking about the non-existing categories and genres, I was referring to the IP 24.149.117.220.
Kind regards,
Iliyana Petkova (talk) 07:37, 2 April 2014 (UTC)

Ageha Chono

Hello,
Ageha doesn't use magic, because she's a human. If you're referring to the 2nd episode, that was all Kamakiri's doing, but he wasn't really well introduced until episode 5.
Regards,
Iliyana Petkova (talk) 09:08, 3 April 2014 (UTC)

Terminology

Hello,
I saw that you've started adding the specific terms on the article and that's why I would like to ask you if I can apply this to the article, but it's still in working progress, because I want to include terms like: "Wuds", "Familiars" and the "Prohibition Law" in question. If you have any suggestions, please tell me. Iliyana Petkova (talk) 08:46, 8 April 2014 (UTC)

Question about energy momentum tensor

Hi, James. I have a question concerning the conservation law of energy-momentum tensor. If possible, please take a look, really appreciated! Gamebm (talk) 19:32, 28 April 2014 (UTC)

"vandalism"

Evidently it wasn't obvious to you (despite the fact that this is a recurring issue, and the reasonably clear edit summary), but this edit is certainly not vandalism: the source of confusion is that User:Walrus068 is thinking of the variable x as real, rather than complex. Probably it would be appropriate to apologize for labeling Walrus068's good-faith edits as vandalism. I will also leave a note for Walrus068 explaining the issue. --JBL (talk) 15:42, 9 May 2014 (UTC)

Walrus068 ignored my previous reversion ("no reason given for apparently incorrect change") and the text in the article saying "All these expansions are valid for complex arguments x.". That shows that he did not care whether what he did was correct or not. Such willful disregard is the essence of vandalism. JRSpriggs (talk) 07:01, 10 May 2014 (UTC)

No, you are completely wrong, as even two seconds reading WP:Vandalism will show. Walrus's second edit shows that Walrus didn't understand your (unexplained) comment. If someone is doing something wrong with good intentions (as was obviously the case here), one can respond by being an ass and calling it vandalism, thereby cutting off any opportunity for constructive engagement while also not explaining to the other party what the problem is, or by taking two minutes to explain the issue (as I did). In the future, you should select the other option. --JBL (talk) 15:05, 10 May 2014 (UTC)

Conversation on inflation?

Hi, I wonder if you remember that I told you a few years ago that I would seriously reconsider my belief in mainstream New Keynesian macroeconomic theory, if inflation exceeded 10% on an annualized basis in any two consecutive months. I believe the last 5 years has been a unique natural experiment and that it confirms the mainstream macro models that:

1. Price inflation is mainly determined by the relative 'slack' in the economy (measured by unemployment above normal, or by production below capacity) - it decelerates when there is positive slack, and accelerates when there is negative slack.
2. The quantity of money may be good as a long run guide, but it little to do with inflation in the short run, especially when the economy is near the zero nominal lower bound.
3. In a modern economy, it is very difficult for wages to fall (and hence deflation to occur), even in the face of depression levels of unemployment.

Given the inflation record of the last few years, I wonder if you would be willing to discuss your beliefs about monetary theory and 'mark to market' your beliefs? LK (talk) 03:05, 28 May 2014 (UTC)

Let me begin by pointing out that, if I recall correctly, you were the one who cut off most of our previous attempts to discuss economics. Although you were often the one to make the last argument, I only refrained from responding because your language made it clear that you did not want to hear my arguments and I did not feel comfortable continuing to argue (on your talk page) with someone under those conditions. Also, I felt that you often read things into what I said that were not there — especially assuming my total agreement with anyone who I mentioned favorably.

A "natural experiment" is not a scientific experiment and cannot serve as a reliable basis for testing hypotheses. In a scientific experiment, the experimenter controls the inputs and deliberately equalizes (or randomizes) the conditions (other than the variable being analyzed) between the control group and the experimental group. In this "natural experiment", there is no control group (indeed no experimental group other than the one case) and no equalizing of the other inputs. Thus any result could be (and probably is) caused by factors other than the variable being analyzed.

I agree that a large quantity of money does not necessarily result in price inflation; there are other considerations.

The ability of the economy to provide jobs has been impaired by taxes, regulations (especially labor law and obamacare), and government spending (raising the cost of raw materials and capital).

Bearing these in mind, if you still want to talk, go ahead. JRSpriggs (talk) 03:10, 29 May 2014 (UTC)

My memory is very bad nowadays, so I don't remember how our last convo ended. If I was brusque with you, I do apologize. I'm not sure if I agree with your assessment about natural experiments. Granted, it's not as good as a double blind random test, but it can be pretty good, and is often the best we have in the social sciences. Given that some events appear to consistently follow certain natural experiments, we can build up certain 'stylized facts' about the behavior of the economy. From this, we reject theories that contradict the stylized facts and try to construct theories that explain them. That's what economics is (at it's best). Science is not forming a set of beliefs, and then looking at the world through colored lenses, interpreting everything in a way to back up one's preconceptions (at least it shouldn't be like that). The last few years appear to have added (or solidified) a few stylized facts to our arsenal, namely 1, 2, and 3 above. LK (talk) 12:17, 30 May 2014 (UTC)

I was not asking for an apology, especially since some of the things I said may have been offensive to you. Rather, I was trying to remind you that in our conversations I have questioned some your ingrained beliefs in ways which may have been disturbing to you. You might want to look back at our previous conversations and consider that possibility before you decide to proceed.

The near impossibility of doing scientific experiments in social science does not mean that we should give more credence to unreliable methods.

I agree that it would be wrong to re-interpret every piece of evidence as necessary to construe it as confirmation of one's favorite hypotheses. However, no field of knowledge (such as economics) can be understood in isolation from the rest of our knowledge of reality. Economic theory must be reconciled with what we know about: physics, chemistry, biology, evolution, psychology, mathematics, business administration, law, politics, ethics, epistemology, metaphysics, etc..

What do you mean by a "stylized fact"? How is it different from an actual fact?

Regarding (1): Is this not just the theory of the Phillips curve which was discredited by the stagflation of the 1970s?

Regarding (2): This appears to be true.

Regarding (3): What do you mean by "modern economy" that would have any bearing on the flexibility of wage rates? If deflation is unlikely to occur, then why has the Federal Reserve been striving so desperately to avoid it?

JRSpriggs (talk) 03:40, 31 May 2014 (UTC)

Economists use the term "stylized fact" to refer to something that (almost) everyone agrees happens most of the time in a certain part of the economy, and that needs to be part of a good theory about that particular part/aspect of the economy.

• Regarding (1): Not at all! What was discredited was the naive assumption (which few actually believed) that we could 'choose' to stably remain a particular point on a stable Philips curve. What came out of it is the theory of short and long run Philips curves. There obviously is a Philips curve in the short run, but persistently being on one side of the Philips curve (e.g. unemployment persistently lower than the natural rate) will cause the short run Philips curve to shift over time.
• Regarding (3): Non-modern (especially agrarian) economies apparently could experience relatively high rates of deflation. Post WWII developed economies (with complex supply chains, long term contracts, unions, etc) apparently cannot. Instead, they fall into economic depression – associated with very low inflation or slight deflation. It is this situation that the Fed is trying to avoid.

Best, LK (talk) 03:02, 10 June 2014 (UTC)

Regarding (1): If you want the Phillips curve to be a scientific theory, you need to specify how it "shifts". That is, you need a formula for the change in the curve's parameters. If you have such, please provide a link to it.

What really bothers me about this is that you are treating the economy as if it were some kind of recalcitrant engine which needs to be tweaked to make it work correctly. You are ignoring the fact that it consists of living people. Those people have their own goals which they are trying to pursue to the extent possible given the contradictory demands of reality and the government bureaucracy. Essentially, the policies you are advocating are a kind of manipulation or deception by which you try to get people to do something which they would not knowingly and freely do.

I do not believe that there is ever any "slack" in the economy. If the owner of a factor of production chooses not to use it, he does so because it is not profitable to do so. Probably because some co-factors of production are missing or prices/regulations have shifted in a way that ruined his plans for it. Or perhaps he is holding onto it against a possible future contingency (a scarcity of that factor). If you trick him into using it (by causing inflation, lending money at unsustainably low interest rates), then it will not end well. You may get a temporary burst of economic activity, but the result will be waste.

Regarding (3): So government and the unions it protects have created a situation where instead of correcting itself quickly via rapid deflation, economic activity is choked-off when deflation would be appropriate. JRSpriggs (talk) 05:24, 12 June 2014 (UTC)

Hi, sorry for the long delay, I've been distracted by other things. Regarding the question of how the Philips curve shifts, you should know that nowadays, almost everything in mainstream economics is rigorously mathematically modeled. For an intro to New Keynesian inflation theory (with graphs but little maths), I suggest Macroeconomics[5], by Hubbard and O'Brien, Chapter 16. For the state of the art, see Interest and Prices: Foundations of a Theory of Monetary Policy[6], by Michael Woodford (warning, probably only readable to people with PhDs in economics). For something for free, here's "Keynesian Macroeconomics without the LM Curve"[7], by David Romer, about how to teach New Keynesian economics to undergraduates. Here's a more mathematical version of the same[8]. Here's an even more mathematical version about teaching the basic model[9].

About slack in the economy, it has often been observed that crowds and mobs can be irrational. E.g. Stock market bubbles; people trampling each other to death during panics; people at a stadium concert all standing, when they could all have a equally good view sitting down. Why not the same for the macroeconomy? The failure to coordinate actions can cause individually rational agents to be collectively irrational. Milton Friedman had an interesting thought experiment on this. Rationality implies that money and prices should be transparent to the real economy — it should be equivalent if bread costs $1 and hourly wages are $2, or if bread costs $5 and hourly wages are $10. An hour of work buys 2 bread. Hence monetary policy should have no effect. Equivalently, it shouldn't matter if we label the hour when the sun is highest as 11:00, 12:00, or 13:00, people rationally should behave the same, changing activities depending on how bright it is. Hence, daylight savings time should have no effect. However, experience proves otherwise — monetary policy and daylight savings time change behavior. Why? Coordination failure. Given long enough, people will adapt no matter what the nominal numbers are, but in the short run, changing nominal numbers have a real effect.

Lastly, I hope you recognize that your (3) is akin to a statement of religious belief. LK (talk) 11:39, 27 June 2014 (UTC)

The paper by Carlin and Soskice is more understandable than most papers on economics, but it contains some simple mathematical errors. They lost a factor of two when they differentiated the cost function of the central bank (although this does not matter since the derivative is then set to zero). More importantly, they ignored the continuing effects (future costs) of uncorrected deviations of the rate of inflation from its target. They arbitrarily assume at one point that some of their constant coefficients are equal to 1. And they never specify the units of the variables and constants in their equations. Also, like most papers, it is much too wordy and yet manages to leave important matters to the guess-work of the reader.

Any attempt by business firms to coordinate their activities to be more rational risks running afoul of government regulations and especially the anti-trust laws. Also it would make their tax returns into an even bigger nightmare (how do they account for the tax consequences of the contingent costs and benefits in their contracts?).

My recognition of the effects of minimum wage laws and the contracts which businesses are compelled to negotiate with various unions is not religion, it is a fact. JRSpriggs (talk) 04:26, 28 June 2014 (UTC)

I probably shouldn't have pointed you at that paper, it's a suggested reformulation, not the standard model. The two previous are better representations of the standard New Keynesian model. It's also an internal working document and not peer reviewed. If you are sure that you have correctly identified errors, you should write the authors, I'm sure they'll appreciate the chance to fix it. BTW, Krugman just posted an interesting blog entry on the history of macro, it's a good read[10].

Your statement that "government and the unions it protects have created a situation where instead of correcting itself quickly via rapid deflation, economic activity is choked-off when deflation would be appropriate" is not a "fact'" - at least not one that 99% of macroeconomists would agree with. In fact more economists would probably agree with these "facts": "Because it is impossible to get rid of market imperfections, an enlightened bureaucrat can always find a way to improve on a market outcome." (See Theory of the second best). "Modest increases in the minimum wage have negligible or slightly positive effect on employment." (See Card & Kruger 1995). LK (talk) 11:17, 2 July 2014 (UTC)

Here we get to what I see as the basic philosophical difference between us. You have this belief that an "enlightened bureaucrat" will be making the government's decisions. That is magical-thinking. Rationality is not something that comes automatically or free of charge. In fact, it is very rare outside of matters within a person's painful and hard-earned experience. That is why the people making decisions should always be those who are directly affected by the results. Hence my belief in freedom and capitalism. JRSpriggs (talk) 10:06, 3 July 2014 (UTC)

I hope you do recognize that both your views and the ones you attribute to me are essentially beliefs, and little different from catechisms like "Jesus Christ is my personal savior". BTW, the way I see the difference in our views is like this. "Motor vehicles exist, they cause pollution and hurt/kill a lot of people every year, however, they are fundamental to our modern lifestyles. I'm in favour of restricting the amount of motor vehicles, using them only where necessary, and improving the way they work and how they fit into our societies. You believe that they are fundamentally evil and favour getting rid of them altogether." Substitute government for motor vehicles in the above, and that's how I see our disagreement. LK (talk) 04:26, 7 July 2014 (UTC)

1. I have good reasons for what I believe, it is not like a religion.

2. Argument by analogy (to automobiles or religion) is not a valid form of argument.

3. Automobiles provide a very large benefit — carrying people and goods from one place to another where they may be more valuable. On the other hand, government has only one "benefit" that is not available in the private sector, it can provide overwhelming force to ensure that it gets its way. But force is inherently destructive, so it is not appropriate to use it except in situations where the target is a net evil which cannot be eradicated by any lesser method.

4. History has shown that governments are almost invariably captured (or originally established) by corrupt people who use them for evil purposes. JRSpriggs (talk) 10:49, 10 July 2014 (UTC)

BLP

I suggest that this edit is in contravention of Wikipedia:Biographies of living persons policy, which "applies to all material about living persons anywhere on Wikipedia". You might like to revert it. Deltahedron (talk) 17:36, 10 July 2014 (UTC)

Thanks for that. Deltahedron (talk) 06:24, 11 July 2014 (UTC)

Thanks for tensor edits!

Thanks (as usual) for the edits, in this case to help correct my additions to tensor.  :)

So I don't clog the talk page with dumb questions: does the distinction you are making mean that the co/contra-variant aspects of the tensor cannot be separately assessed (in a meaningful way)? I was thinking dimensions b/c of the contribution to the dimensionality of the final matrix (and in a sense the dimensionality of the tensor as a whole), but I wish to understand where the flaw is in my perception. TricksterWolf (talk) 19:17, 12 August 2014 (UTC)

One does not normally talk about the dimensions of the array, perhaps because of the possibility of confusion with the dimensionality of the underlying space.

Each dimension of the array is associated with one index. The index ranges over a finite number of values — each value corresponding to one of the dimensions of the underlying space. So a tensor with type (1, 1) over a ten-dimensional underlying vector space would consist of a 10×10 matrix having one hundred components. Each row is associated with a distinct element in the basis of the underlying vector space. Each column is associated with an element of the basis of the covector space dual to the vector space.

If the underlying vector space has d dimensions, then a tensor of type (n, m) will have d<sup>n+m</sup> components each of which is a real number (or a real valued function of location on the manifold, if we are talking about a tensor field). Is that clear? JRSpriggs (talk) 23:55, 12 August 2014 (UTC)

ISIS & the ISI

Hello, there. Although I wasn't before, I am now concerned about the length of the ISIS page and Gazkthul as you will have seen has suggested doing with the ISI group what he did with ISIS's earlier predecessors, giving it its own article and leaving a resume in "History" in the ISIS page, which would reduce the size of the "History" section considerably. He will need to know whether he has consensus to do this and I wonder if I could ask you to give your response at the end of the thread here, pro or con. I cannot see why the 2014 timeline is duplicated on this page when it already has its own article! Reducing the ISI section and removing the 2014 timeline would drastically reduce the article's size! Thanks for telling the IP how to go about becoming an editor; the page could do with some more input. BTW, there has still been no response to my request at the WP:RSN about the Israel citations! It was even archived at one point, but I retrieved it and put it back in the list. --P123ct1 (talk) 12:08, 23 September 2014 (UTC)

deleted talk stuff on natural numbers

Hello JR it is nice to make your acquaintance.

Yeah of course I'm not out to delete other contributions. What you don't see is that there was a second half of that conversation already deleted by MjolnirPants. Rather than deleting it directly he said he was moving it to another section, put the pointer for the move, but the text never appeared in the other section. It could have been an accident. I don't mind. He now seems to be excited about my observation that there is a conflict here between formal math definition and what school book writers would like to see. He has opened a talk section on that. I think it will be productive.

Wikipedia does allow for talk page "refactoring", and I do think that section should go according to those guidelines. https://en.wikipedia.org/wiki/Wikipedia:Refactoring_talk_pages

There was an effort to prevent zero from being mentioned as a natural when I arrived at the site. The first sentence was a circular definition and called naturals {1,2, 3... } etc. The point about not linking to other pages is correct. Every time I mentioned zero, my edit was deleted. When I added pointers to the set-theoretic natural number, my edit ws deleted. When I gave the first of Peano's axioms, zero is a natural, it was deleted - despite being on the page about the Peano axioms. When I pointed out that zero is an additive identity needed in arithmetic, my edit was deleted. When I mention Von Neuman's definition my edit was deleted. When I copied another editors comment that "The convention used by set theorists .." it was deleted as was the other editors remark. It is back now. When I fixed the circular definition on whole numbers, that was deleted... These deletes were often when ignoring my talk page entries. Majorpants ignored six talk page entries and the confirmation of two editors when he deleted stuff.

So yeah, I wish people would have more respect about deletes. You didn't ask me about my edit before you reverted it either. I have a talk page.

Now I'm on the fence about "refactoring" and talking out that section about the war on zero because people don't understand it without more context, and it is too much work to put the links to the deletions mentioned above in order to support the point, but most of all it is not on the topic of natural numbers but on the topic of editor etiquette. Besides what good does it do? Furthermore it isn't fair that my text stays but the other text goes.

So I hope you understand why I might refactor that out. — Preceding unsigned comment added by Thomas Walker Lynch (talk • contribs) 18:40, 8 October 2014 (UTC)

graph cuts

hi you seem to be a math/stats guy. I was trying to make sense of Cut (graph theory) and was struggling, and tagged it for being too technical, and was drilled on per Talk:Cut_(graph_theory)#Technical. Maybe you might be willing to add some discussion to that article to make it more understandable to your average college educated person at least? thanks for considering... Jytdog (talk) 01:22, 24 October 2014 (UTC)

Sorry. Graph theory is not an aspect of mathematics to which I have paid much attention. So anything I said on that subject would be no better than what a layman might say. JRSpriggs (talk) 12:26, 24 October 2014 (UTC)

thanks for having a look and replying! Jytdog (talk) 12:34, 24 October 2014 (UTC)

Loving relation in FOL-article

Hi! Thank you for looking after my tinkering there. I only by chance stepped into this article and you were so kind to repair my rubbish. Just now I noticed this and tried to improve by marginals again. I am fully OK with substituting formulas for formulae, but like to remark that I deliberately chose someone loves someone over everyone loves someone, because I feel less a priori quantification in the former formulation. This is not to say that I want to revert it, but just give a reason for me doing so. Sorry, if I bothered you. Purgy (talk) 08:00, 11 December 2014 (UTC)

I just felt that the examples in first sentence of First-order logic#Loving relation should agree with one another to avoid confusing the readers. If you want to change both of them, while retaining their agreement, then go ahead. JRSpriggs (talk) 15:44, 11 December 2014 (UTC)

If I ever get the feeling I could do some substantial improvement to this article, I'll reconsider this idea. :) Thanks! Purgy (talk) 17:59, 11 December 2014 (UTC)

Lagrangian of a free particle in GR

OK, here I will give a detailed discussion. First, some notes on Lagrangian and actions, as well as the geodesic equation:

• The Lagrangian is unphysical.
• The action is unphysical.
• Lagrangians and actions are equivalent if they generate the same equations of motion.
• δS=0 implies the Euler-Lagrange equations, not the other way around.
• Overall factors in the Lagrangian are irrelevant. This includes signs and constants.
• The geodesic equation does not rest on an Euler-Lagrange style argument. It can be derived by other methods.
• The mass shell condition is a consequence of the geodesic equation.

The first three are basic tenets of the Lagrangian prescription. See any textbook on QFT and you will see Lagrangians and actions mangled and beaten into shape to extract physical information. Now, because of the linearity of integration and functional differentiation, if the Lagrangian is multiple of something else, then that multiple cancels in δS=0, leaving the equations of motion unaffected.

Some comments on your "talk" post:

• How does one derive the geodesic equation from your Lagrangian? That Lagrangian IS correct, in a sense, as I will show later. However, it is not in a form that I can see leading to the properly parametrized geodesic equation. (A multiple of τ is the correct parameterization.)
• The units really don't matter. I could be using units in which m=c=1. This does not affect anything.
• The Newtonian argument breaks down when we consider massless particles. For such particles your action is zero! By your reasoning, this leads to trivial equations of motion.

First I will show that the geodesic equation is not strictly a consequence of δS=0. For this, I will adapt the discussion found in Weinberg's Gravitation and Cosmology. Let ξ be a locally inertial coordinate system (free-falling) and τ be the proper time along the worldline (the time on a clock as measured by the particle in its rest frame). According to the Principle of Equivalence, there is such a coordinate system in which the equation of motion for SR holds:

${\frac {d^{2}\xi ^{\alpha }}{d\tau ^{2}}}=0$

In natural units, the proper time in this frame is

$d\tau ^{2}=-\eta _{\alpha \beta }d\xi ^{\alpha }d\xi ^{\beta }$

Now suppose we use any other coordinate system x, which may be a cartesian system in a laboratory, curvilinear, accelerated, or whatever. The freely falling coordinates ξ are functions of the x, thus the first equation becomes

$0={\frac {d}{d\tau }}\left({\frac {\partial \xi ^{\alpha }}{\partial x^{\mu }}}{\frac {dx^{\mu }}{d\tau }}\right)={\frac {\partial \xi ^{\alpha }}{\partial x^{\mu }}}{\frac {d^{2}x^{\mu }}{d\tau ^{2}}}+{\frac {\partial ^{2}\xi ^{\alpha }}{\partial x^{\mu }\partial x^{\nu }}}{\frac {dx^{\mu }}{d\tau }}{\frac {dx^{\nu }}{d\tau }}$

A line of algebra and the chain rule leads to the geodesic equaton

${\frac {d^{2}x^{\lambda }}{d\tau ^{2}}}+\Gamma _{\;\;\mu \nu }^{\lambda }{\frac {dx^{\mu }}{d\tau }}{\frac {dx^{\nu }}{d\tau }}=0$

where

$\Gamma _{\;\;\mu \nu }^{\lambda }={\frac {\partial x^{\lambda }}{\partial \xi ^{\alpha }}}{\frac {\partial ^{2}\xi ^{\alpha }}{\partial x^{\mu }\partial x^{\nu }}}$

is the affine connection. The proper time may also be written in an arbitrary coordinate system:

$d\tau ^{2}=-\eta _{\alpha \beta }{\frac {\partial \xi ^{\alpha }}{\partial x^{\mu }}}dx^{\mu }{\frac {\partial \xi ^{\beta }}{\partial x^{\nu }}}dx^{\nu }=-g_{\mu \nu }dx^{\mu }dx^{\nu }$

where g is the metric tensor

$g_{\mu \nu }=\eta _{\alpha \beta }{\frac {\partial \xi ^{\alpha }}{\partial x^{\mu }}}{\frac {\partial \xi ^{\beta }}{\partial x^{\nu }}}$

Denote by $\partial _{\mu }$ the operator $\partial /\partial x^{\mu }$. You can have the pleasure of verifying that, given the previous equations

$\partial _{\lambda }g_{\mu \nu }=\Gamma _{\;\;\lambda \mu }^{\rho }g_{\rho \nu }+\Gamma _{\;\;\lambda \nu }^{\rho }g_{\rho \mu }$

Add to this equation the same equation with μ and λ interchanged and subtract the same equation with ν and λ interchanged. Remembering that the affine connection as defined above is guaranteed to be symmetric, this leads to the usual Christoffel symbols

$\Gamma _{\;\;\mu \nu }^{\lambda }={\frac {1}{2}}g^{\lambda \rho }(\partial _{\mu }g_{\nu \rho }+\partial _{\nu }g_{\mu \rho }-\partial _{\rho }g_{\mu \nu })$

So it is easy to see that the geodesic equation does not rest upon any particular variational principle of any particular Lagrangian, because you don't need the action principle to derive it.

From here on I will use some coordinate free notation mixed in with the usual Ricci notation. Let γ(τ) be the worline of the particle, parameterized by the proper time τ. Let (M, g) be a 4-dimensional pseudo-Riemannian manifold with a Lorentz metric g and inner product $\langle .,.\rangle =g(.,.)$. Let $\nabla$ be the Levi-Civita connection on M. Let

${\dot {\gamma }}={\frac {d}{d\tau }}$

be the tangent vector to the curve. In this notation, the geodesic equation is

$\nabla _{\dot {\gamma }}{\dot {\gamma }}=0$

i.e. the tangent vector is autoparallel along the geodesic. Next we use the Ricci identity. See any text on differential geometry for a proof. For any three vectors X, Y and Z

$X\langle Y,Z\rangle =\langle \nabla _{X}Y,Z\rangle +\langle Y,\nabla _{X}Z\rangle$

So let $X=Y=Z={\dot {\gamma }}$. Then

${\frac {d}{d\tau }}\langle {\dot {\gamma }},{\dot {\gamma }}\rangle ={\dot {\gamma }}\langle {\dot {\gamma }},{\dot {\gamma }}\rangle =2\langle \nabla _{\dot {\gamma }}{\dot {\gamma }},{\dot {\gamma }}\rangle =0$

where the last equality follows from the geodesic equation. We integrate the very first term along the worldline P. Thus

$\langle {\dot {\gamma }},{\dot {\gamma }}\rangle ={\text{const}}$

The convention is to take this constant to be -1. This comes about as follows. Suppose a particle in SR travels along a worldline P. Then the change in proper time is given by the line integral

$\Delta \tau =\int _{P}d\tau =\int _{P}{\sqrt {-\eta _{\alpha \beta }d\xi ^{\alpha }d\xi ^{\beta }}}$

Now suppose we turn on the gravitational field. Then by the Equivalence Principle (I will drop the P from now on)

$\Delta \tau =\int {\sqrt {-g_{\mu \nu }dx^{\mu }dx^{\nu }}}$

You object that the integral is not in the form ∫f(x)dx. So we choose to parameterize using the proper time and write

$\Delta \tau =\int {\sqrt {-\langle {\dot {\gamma }},{\dot {\gamma }}\rangle }}\,d\tau$

Comparing with above, we conclude that the choice

$\langle {\dot {\gamma }},{\dot {\gamma }}\rangle =-1$

is consistent. But what if we choose some other parameter λ? As of this moment we have no restrictions on what can be a parameter. Thus

$\Delta \tau =\int {\sqrt {-\langle {\bar {\gamma }},{\bar {\gamma }}\rangle }}\,d\lambda$

where

${\bar {\gamma }}={\frac {d}{d\lambda }}$

Now I want to bring the action principle into the fold. I think that we can both agree that in SR, if we care about overall signs and factors (c=1 still remains though), the free action for a point particle of mass m is

$S=-m\int {\sqrt {1-{\vec {v}}^{2}}}\,dt=-m\int d\tau$

The GR generalization is

$S=-m\int d\tau =-m\int {\sqrt {-\langle {\bar {\gamma }},{\bar {\gamma }}\rangle }}\,d\lambda$

The principle of least action is of course δS=0. Now I hope you see that the factor -m does not do anything at all! Thus the variational principle is simply

$\delta \int {\sqrt {-\langle {\bar {\gamma }},{\bar {\gamma }}\rangle }}\,d\lambda =0$

I also hope you see that $\langle {\bar {\gamma }},{\bar {\gamma }}\rangle$ is in no way restricted or fixed and can thus S can be varied. In this article this variation is performed. I will not do it here. The result is

${\frac {d^{2}x^{\lambda }}{d\lambda ^{2}}}+\Gamma _{\;\;\mu \nu }^{\lambda }{\frac {dx^{\mu }}{d\lambda }}{\frac {dx^{\nu }}{d\lambda }}=0\quad {\text{or}}\quad \nabla _{\bar {\gamma }}{\bar {\gamma }}=0$

Once again we can easily show that

$\langle {\bar {\gamma }},{\bar {\gamma }}\rangle ={\text{const}}$

from which it follows that $\lambda \propto \tau$. This follows only from the equations of motion and is not obvious before. As a constraint derived from the equations of motion, it cannot be applied to the Lagrangian! This would be like doing QFT on the mass shell only. (In fact, as I will show, the mass shell condition is a consequence of the geodesic equation.)

I said that the Lagrangian you presented was not incorrect. This is because you have defined the action as

$S=\int L\,dt$

whereas I have defined it as

$S=\int L\,d\tau$

This is a simple change of parametrization. However, your Lagrangian is not invariant under diffeomorphisms. The coordinate t has a nontrivial transformation rule as opposed to λ, which allows for invariant parameterization. Some food for thought: try deriving the geodesic equation from your Lagrangian. Maybe you can surprise me and get it.

The current discussion is adapted from Becker, Becker & Schwarz String Theory and M-Theory. The action -m ∫dτ has some problems with it:

• In the path integral sense, it is a disaster. The square root makes this very hard to quantize.
• It is completely unsuited to handling massless particles for obvious reasons.

These problems can be circumvented by introducing an auxiliary (bosonic) field α(τ) in the modified action

$S={\frac {1}{2}}\int d\lambda \,\left({\frac {\langle {\bar {\gamma }},{\bar {\gamma }}\rangle }{\alpha }}-m^{2}\alpha \right)$

First we determine the equations of motion for α(τ):

${\frac {\delta S}{\delta \alpha }}=-{\frac {1}{2}}\left({\frac {\langle {\bar {\gamma }},{\bar {\gamma }}\rangle }{\alpha ^{2}}}+m^{2}\right)=0\longrightarrow \langle {\bar {\gamma }},{\bar {\gamma }}\rangle =-m^{2}\alpha ^{2}$

Plugging this back into S, we see that we recover the original action. Now, it may be shown that this modified action is parameterization invariant if α has certain transformation properties. (BBS exercise 2.3) This leads to a sort of gauge invariance. The gauge α=1 is nice. In this gauge

$\langle {\bar {\gamma }},{\bar {\gamma }}\rangle =-m^{2}$

is the familiar mass shell condition. This means ${\bar {\gamma }}$ is the momentum vector. The additive constant in the Lagrangian can be just thrown away because it contributes nothing to the equations for γ. Thus the action is effectively

$S={\frac {1}{2}}\int \langle {\bar {\gamma }},{\bar {\gamma }}\rangle \,d\lambda$

Now this makes perfect sense for massless particles. For massive particles, we have τ=mλ. So, up to an overall factor (which we just throw away, the 1/2 is kept for historical reasons)

$S={\frac {1}{2}}\int \langle {\dot {\gamma }},{\dot {\gamma }}\rangle \,d\tau$

As I showed in the post you deleted, this leads to the geodesic equation

$\nabla _{\dot {\gamma }}{\dot {\gamma }}=0$

The really nice thing about this action is that it is computationally simple to work with.

Thus, the Lagrangian of general relativity can be taken to be

$L={\frac {1}{2}}g_{\mu \nu }{\dot {x}}^{\mu }{\dot {x}}^{\nu }$

Because this leads to the correct equations of motion, it is an acceptable Lagrangian.

I hope this clears up any confusion.

Differential 0celo7 (talk) 22:43, 18 December 2014 (UTC)

It would have been better to hold this discussion at Talk:Lagrangian#What is the correct Lagrangian for an isolated test particle in general relativity? so that other interested people could find it and participate.

Much of what you say is true and already well known to me. However, I disagree on some important points.

I disagree about ignoring constant factors because we may wish to add Lagrangians for various parts of a system together to get the Lagrangian for the total system and this will fail unless their proportions are correct. Also you need the constant factors to get the correct stress-energy tensor from the Lagrangian.

Your Lagrangian was either pulled out of the air and justified by its results (which I think should be avoided when possible) or it is an attempt to generalize ${\frac {mv^{2}}{2}}$ in an inappropriate way.

I do not disagree with the geodesic equation, but only with your method of deriving it.

I have shown how to derive a variation of the geodesic equation (using momentum) from my Lagrangian at User:JRSpriggs/Force in general relativity#Derivation from Lagrangian.

I have not yet seen a fully satisfactory derivation of the equation of motion for massless particles except by taking a limit of the equation for massive particles as the mass approaches zero. However, the only particles which might be massless are the photon and the graviton (if it exists).

Using the proper-time τ as a parameter for the particle's path is inappropriate because the value of τ is path-dependent. In particular, the limits of integration might have to be changed as you do the variation which is highly undesirable. JRSpriggs (talk) 12:27, 19 December 2014 (UTC)

I'll move the discussion to the Lagrangian talk page.

Differential 0celo7 (talk) 19:55, 19 December 2014 (UTC)

Invitation

	You've been invited to be part of WikiProject Cosmology
	Hello. Your contributions to Wikipedia have been analyzed and it seems that this new Wikiproject would be interesting to you. I hope you can contribute to it by expanding the main page and later start editing the articles in its scope. Make sure to check out the Talk page for more information! Cheers Tetra quark (talk) 20:23, 30 December 2014 (UTC)

Invitation to Participate in a WikiProject Study

Hello JRSpriggs,

We’d like to invite you to participate in a study that aims to explore how WikiProject members coordinate activities of distributed group members to complete project goals. We are specifically seeking to talk to people who have been active in at least one WikiProject in their time in Wikipedia. Compensation will be provided to each participant in the form of a $10 Amazon gift card.

The purpose of this study is to better understanding the coordination practices of Wikipedians active within WikiProjects, and to explore the potential for tool-mediated coordination to improve those practices. Interviews will be semi-structured, and should last between 45-60 minutes. If you decide to participate, we will schedule an appointment for the online chat session. During the appointment you will be asked some basic questions about your experience interacting in WikiProjects, how that process has worked for you in the past and what ideas you might have to improve the future.

You must be over 18 years old, speak English, and you must currently be or have been at one time an active member of a WikiProject. The interview can be conducted over an audio chatting channel such as Skype or Google Hangouts, or via an instant messaging client. If you have questions about the research or are interested in participating, please contact Michael Gilbert at (206) 354-3741 or by email at mdg@uw.edu.

We cannot guarantee the confidentiality of information sent by email.

The link to the relevant research page is m:Research:Means_and_methods_of_coordination_in_WikiProjects

Ryzhou (talk) 03:55, 28 January 2015 (UTC)

Remark on politics

On your user page, you write the following:

"A free economy based on private property tends to correct itself by the process of natural selection. Any attempt by a government planner to manage the economy will necessarily be misguided due to his limited knowledge and the destructive force necessary to attempt such management. Invariably the attempt will damage the economy and work against the interests of everyone including the intended beneficiaries.

All entitlement programs (obamacare, social security, medicare, medicaid, welfare, etc.) should be repealed immediately because they are: outside the proper functions of government, promoters of dependency, too costly, and unsustainable."

I agree that natural selection might be one of the forces ruling the market. It might work as follows: Those companies which make the most profits survive, while those making less profits go bankrupt. I imagine that if the government intervenes for instance by taxing CO<sub>2</sub> emissions, the companies will produce less CO<sub>2</sub>, since they make more money then. This, I think, would be an example for a non-misguided government intervention. --Mathmensch (talk) 09:53, 11 February 2015 (UTC)

Businesses making a profit may survive. Businesses which suffer a loss and continue to do so will be forced to liquidate.

You do not know how harmful carbon-dioxide emissions are or even whether they are harmful rather than beneficial. Neither do politicians and bureaucrats. But what is clear is that taxation and the violence which is required to collect taxes is very harmful.

Imagine that someone was going around your neighborhood (at night) siphoning gasoline out of your vehicles. How would you feel? Perhaps you cannot make it to work on time. Perhaps you cannot use your car in an emergency. What if the perpetrator was caught and his defense was that he was protecting the planet from your carbon-dioxide emissions? JRSpriggs (talk) 08:49, 13 February 2015 (UTC)

I only use public transport in order to avoid extensive CO<sub>2</sub> emissions. I think I would probably be O.K. with somebody stealing my stuff if they have better use for it.

On the basis of what I currently know, I personally would guess that carbon-dioxide emissions are probably heating up earth because of the greenhouse effect. This is for example depicted in this picture:

There are certain issues connected to this effect, which go against my (utilitarian) ethics. These include increased extreme weather (which can damage people). Extreme weather comes about more often with increased CO<sub>2</sub> emissions, because almost all weather phenomenons are triggered by energy in the atmosphere, and this energy in turn is increased by the greenhouse effect. I list tornadoes, for example, as an extreme weather phenomenon triggered by high energy in the atmosphere.

Another issue are the effects on crops. In the equatorial region, for the next 100 or something years we expect a population growth by three billion. However, these regions are also those where crop growth is predicted to go back. I don't know of firm evidence confirming that there will be compensation in higher latitude countries, but even if there is, it is by no means certain that the crops are transported from there to the regions where they are needed.

And further, if one would give weight to the biodiversity of this planet: If the environmental conditions change, many species might not have the chance to migrate to an area where the ecological circumstances which they need prevail. This could in some cases even trigger species extinction (see Climate change and ecosystems). --Mathmensch (talk) 22:04, 13 February 2015 (UTC)

You should be more concerned for your own needs rather than tolerating someone stealing your energy (or regulating or taxing it).

Carbon-dioxide emissions do raise the temperature of the Earth a little, but the effect is very small.

The increased heat in the atmosphere due to the greenhouse effect is merely increasing the temperature of the heat sink, not the heat source. Thus it will reduce the output of the weather 'engine' rather than increasing it. Also it is recentism to think that recent extremes of weather are unusual; extremes of weather (and climate change) have occurred in all epochs of time.

Even before people appeared, species went extinct (and were replaced by new species) with great frequency. Most of those species were no great loss to the world — they were too fragile (inflexible) and too specialized to provide any substantial benefit to others. JRSpriggs (talk) 19:25, 15 February 2015 (UTC)

You might also be interested in "The Climate Change Solution No One Will Talk About" by Stefan Molyneux. JRSpriggs (talk) 04:55, 17 February 2015 (UTC)

Actually, I am more worried about a new Ice age in which the United States and Canada are crushed under a huge ice sheet (glacier) rather than global warming. Northern Eurasia would also be covered in ice. JRSpriggs (talk) 17:29, 23 February 2015 (UTC)

See "What it would take to prove global warming". JRSpriggs (talk) 04:20, 23 April 2015 (UTC)

Redlinks?

Hi; sorry if I'm being blind, but by this revert you are implying that you seen something on that page.. currently to me the page User:Mathbot/List of mathematical redlinks lists a single list, which is blue: List of Italian mathematicians.. I agree that list contains some redlinks.. is that what you are talking about? Maybe I'm getting confused, but that page does not seem to do what it claims to do. I would quite like to see a list of redlink, like User:Mathbot/Most wanted redlinks, but alas it has not been updated since 2007. So I'm not sure it's worth linking to.. Mark M (talk) 10:22, 5 March 2015 (UTC)

Yes, you are being blind. Besides the link you mentioned (to Italian mathematicians), that page contains links labelled "0-9", "A", "B", ..., "Z" and below those a link to the other page you mentioned "User:Mathbot/Most wanted redlinks". Try reading the text. JRSpriggs (talk) 00:51, 6 March 2015 (UTC)

Haha, I don't know how I missed that. I see it now. It is unfortunate this list is so out of date.. after a quick (and admittedly small) sampling, it seems that a large proportion (possibly more than half) of the listed articles are either no longer red, or no longer have any incoming links. But I suppose there isn't anything better at the moment. Cheers, Mark M (talk) 09:10, 6 March 2015 (UTC)

I asked Oleg Alexandrov (talk · contribs) to have Mathbot (talk · contribs) update the lists. It last did so in 2007. So there might be a question about whether it still has the capability to do that. JRSpriggs (talk) 15:55, 6 March 2015 (UTC)

Recursively enumerable set

Hey JR, what's wrong with the change you reverted?

https://en.wikipedia.org/w/index.php?title=Recursively_enumerable_set&oldid=651019471&diff=prev

• If it's correct, it's 3 times shorter and far more easy to understand.

• If it's incorrect, please tell me why. It's not an ego thing; in fact it's the opposite. It would mean that my understanding of recursively enumerable sets is incomplete. To me, that would be appalling (really, and for several reasons).

Thank you for educating me! I love being educated, fast and deep.☺

--Verdana♥Bøld 10:34, 14 March 2015 (UTC)

As I said in my edit summary, your "definition" of recursively enumerable set is unclear and thus not a definition. It could be interpreted in a way which would make it correct, but it could also be interpreted in other ways which are incorrect.

You said "A set is recursively enumerable if there exists an algorithm that maps each element of the set, in finite time, to a unique natural number.". You failed to restrict the set to be a set of natural numbers. This opens a can of worms about how the correspondence with natural numbers should be done. "Algorithm" is vague, whereas there is a precise mathematical definition of "partial recursive function". "In finite time" could mean finitely many steps of a calculation, but it could mean something else. "To a unique natural number" could mean that only one natural number is in the range (which while equivalent is a different definition from the one we were using) rather than that the function is at most single valued.

In any case, there is already an informal definition like yours in the lead. The section which you changed was supposed to be for the technically correct and precise definition. Also the (old) sources I am familiar with use a definition like mine rather than yours, and we are supposed to follow the sources (in case of doubt). JRSpriggs (talk) 03:02, 16 March 2015 (UTC)

Conjugate variables in QM

I suppose you have completed this section [11]. For research purposes, if you have the sources I might need them, however if you proved them yourself, I might be very interested in the proofs. Especially the electric potential-charge density uncertainty seems to have some implications in nano-communications. I would be extremely grateful if you could help me out with this. I have a BS in both electrical engineering and physics and an MS in electrical engineering so I might follow your work.

As a side note, I am also a go player. I rank 5k in KGS. I might be a little obsolete, but if you are close to my rank, we may play :) Thank you! Caglarkoca (talk) 00:52, 13 May 2015 (UTC)

The article on the Hamilton–Jacobi equation may be helpful in understanding this. I no longer remember where I got the information on the conjugate variables. But you might see Covariant formulation of classical electromagnetism#Lagrangian for classical electrodynamics, the subsection on "Matter" where it gives the Lagrangian in non-relativistic notation.

I am not an active GO player at this time and I never got above 10 kyu at best. I am probably closer to 18 kyu now. JRSpriggs (talk) 02:05, 14 May 2015 (UTC)

The electromagnetic items on the list are wrong because they are derivatives of the Lagrangian rather than the action. However, if everything that is questionable were removed from the article, then there would not be much, if anything, left. So I gave up on it and took it off my watch list some time back. JRSpriggs (talk) 03:10, 14 May 2015 (UTC)

Thank you for your time. I'll check them anyway. But you are wrong about Go. You being around 18k and me being 5k does not prevent us from playing it. Contact me if you are interested in a teaching or handicap game :) 212.175.32.131 (talk) 08:01, 14 May 2015 (UTC)

Einstein Field Equations

Hello Mr JRSpriggs, Could you please explain deleting the application section you judged to be no value? The 2 references and application were valuable to me, and I believed to others, especially to new learners. Thank you, --Jcardazzi (talk) 11:49, 21 August 2015 (UTC)jcardazzi

I still believe that the section you added, Einstein field equations#Simple Application and Meaning, has no value. Presently, it says "Solving the equation by using the values for the physical constants on the right side of the field equation, where G=Newton's gravitational constant, c=the speed of light, the equation reduces to: G=0.00000000000000000000000000000000000000000000002*T meaning to get a warp of space-time takes a large amount of mass. For example the Earth's mass at 1 M⊕ = 5.97219 × 1024 kg warps space-time to the strength of gravity which we experience on Earth causing an acceleration of mass of approximately 9.8 meters/second2 at the Earth's surface.". A long string of zeros (instead of an expression in scientific notation) is incomprehensible as most people would have difficulty even counting the number of zeros, let alone figuring out what they mean. Presumably you are assuming some system of units, but you have not identified which system. No scientist talks about "a warp of space-time"; that is straight out of fiction. The "G" in your formula is potentially confusing as some people might read it as referring to the gravitational constant rather than the Einstein tensor. Finally, your section amounts to saying that the mass of the Earth is responsible for the Earth's gravitational field. Well, duh!!! Thus I will remove it again. JRSpriggs (talk) 23:36, 23 August 2015 (UTC)

---

Hello Mr JRSpriggs, thank you for the comments, they are in informative to me. I will try to rework the wording from the references and your comments for better clarity, and propose them in the talk page in the future.

---

Regarding the term: "a warp of spacetime";

I read the term and similar uses of it, in many articles, for example: https://en.wikipedia.org/wiki/Introduction_to_general_relativity "...According to general relativity, the observed gravitational effect between masses results from their warping of spacetime."

"High-precision test of general relativity by the Cassini space probe....radio signals sent between the Earth and the probe... are delayed by the warping of spacetime...due to the Sun's mass.

Also, fyi, here is an article on the physics of space warp experiments: https://en.wikipedia.org/wiki/Warp-field_experiments

a book using the term: http://www.its.caltech.edu/~kip/scripts/PubScans/VI-47.pdf General relativity is Einstein’s law of gravity, his explanation of that fundamental force which holds us to the surface of the Earth. Gravity, Einstein asserted, is caused by a warping of space and time—or, in a language we physicists prefer, by a warping of spacetime.

---

Thank you,--Jcardazzi (talk) 00:33, 24 August 2015 (UTC)jcardazzi

Lagrangian

Hi James, good to see you here. I tidied up after my bad CSD suggestion. Ooo, while I'm here, now that Mathjax support has been removed, how are you guys getting proper rendering? I came across an abandoned script that enables it again, was thinking of hosting it. Does that sound useful? Regards Widefox; talk 15:35, 11 September 2015 (UTC)

Countable sets

Thanks for the edits, I sometimes get a little too sloppy when composing and it is nice to know that other eyes will catch my slip-ups. In the proposition you modified, I had left the disjoint condition in, just to be faithful to the reference, which leads me to the question I wanted to ask you. I am contemplating putting in a remark at the beginning of the section saying that the functions being used may not be precisely as presented in the references, but that the differences are minor. It should have been, but wasn't, easy to find references that presented things using the conventions of the article. Most of my goto sources do not consider 0 to be a natural number and many of them only define the functions in the denumerable case with N as the domain. Of course it is trivial to fix these problems, but the reader who goes off for more information in the references is not going to see the exact statements that appear in the article. Hence, I see a need for the disclaimer. I would be interested to know what you think about putting that in. Thanks. Bill Cherowitzo (talk) 03:52, 19 September 2015 (UTC)

ArbCom elections are now open!

Hi,
You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 13:47, 23 November 2015 (UTC)

Reverted edit to "Lawrence Kohlberg's stages of moral development"

Could you please provide me a more detailed rationale for your reversion of my edit? Is the "girl/boy" idea a direct quote from the source? If so, "kid" probably wasn't a great idea on my part, but with some rephrasing "girl/boy" could be removed entirely without the use of "kid". I haven't been able to get a copy of the source paper, but I have looked into other papers written about the original paper and they all manage to avoid "girl/boy", so I think it is fair to expect Wikipedia to do the same. I am interested in improving the quality of the article and not partaking in an edit war or argument, so I want to know why my edit was reverted in order to potentially find a better way of including it in the article. Thanks for your time and your contributions to the article! Falkirks<sup>Talk</sup> 15:51, 11 December 2015 (UTC)

I meant to explain in my edit summary, but something went wrong and my edit was saved before I could type in the edit summary.

The word "kid" is too informal for an encyclopedia. Strictly speaking, it refers to baby goats not people. Thus it could be seen as insulting to children generally.

You explained your change to Lawrence Kohlberg's stages of moral development with the summary "Changed 'boy/girl' to 'kid' to be more clear and remove potential transphobic connotations". I think that you are worried unnecessarily. Everyone knows that "boy/girl" in this context is short for "boy or girl". Virtually no one (other than yourself apparently) is even going to think about transgender issues in relation to this article. And if we made a change that caused them to think about it, that would be distracting from the topic of the article and thus wrong. JRSpriggs (talk) 11:36, 13 December 2015 (UTC)

Thanks for your explanation. I am glad that the lack of summary was accidental. My concern is that "boy or girl" enforces the idea of a Gender binary which in my opinion is outside of the scope of this article. If one reads the article on Gender they will notice that Wikipedia discusses identities that can't be defined as "boy or girl", this article excludes those identities. I am not seeking revolution for my way of thinking, I am simply looking for consistency throughout the encyclopedia with regards to inclusion of non-binary gender identities. The issue is much more blatant than you portray it as and I firmly believe that it deserves some remedy. The idea that "kid" refers more to goats than people went completely over my head and I hope that a better word exists. Do you have any suggestions for a gender neutral term that could be used in place of "kid"? Falkirks<sup>Talk</sup> 18:13, 15 December 2015 (UTC)

You could say "child". However, in the real world people say "boy" or "girl" as appropriate. Recognizing a person's sex is considered polite. The fact that our language leaves out other (extremely rare) alternatives is unfortunate, but it is not the function of Wikipedia to try to revise the world. JRSpriggs (talk) 18:27, 15 December 2015 (UTC)

Re: Sanders

The sort of people who support Bernie Sanders may (mostly) believe that the United States is a plutocracy. But that is not true for the majority of Americans.

I think you're wrong on this one. Sanders has worked closely with conservatives on many issues, and while they may disagree on the exact path to take to get to the solution, for the most part, they all agree on the nature of the problem. This is also true for the majority of Americans.[12] So I think the facts just don't support you on this. The use and misuse of the word "socialism" seems to be your sore point, but pork spending, corporate welfare, health care and job security are all things Americans are on the same page about. The thing is, when you are too extreme, and too far to the right, mainstream ideas like those of Sanders are perceived as radical, when in fact they are considered center to center left in relation to the rest of the world. Viriditas (talk) 20:16, 27 December 2015 (UTC)

Category:Relativists

Category:Relativists, which you created, has been nominated for possible deletion, merging, or renaming. If you would like to participate in the discussion, you are invited to add your comments at the category's entry on the Categories for discussion page. Thank you. —Justin (koavf)❤T☮C☺M☯ 06:15, 30 December 2015 (UTC)

Johann Kudar's elevation to notability

Just a brief note that I do feel strongly Johann Kudar does not rise to the notability level of an article implicitly proposed by the redlink in the Klein-Gordon equation I deleted, evidently without success. Come on: Johann Kudar? What were these guys thinking?? Cuzkatzimhut (talk) 03:28, 26 January 2016 (UTC)

Reverting for no reason is highly disruptive

You undid an edit of mine without bothering to explain why.[13] This is rude and highly disruptive behaviour. If you had a reason to revert, you should have specified it in the edit summary, and if you didn't, you shouldn't have reverted. 109.155.216.108 (talk) 11:46, 12 February 2016 (UTC)

If you knew anything about the book, you would realize that the information you removed was all true, relevant, and important. You are vandalizing the article and using "policy" as an excuse. JRSpriggs (talk) 05:04, 13 February 2016 (UTC)

Don't make personal attacks. I'll report future occurrences. Later on today I'll go through the changes and explain to you one by one why they are necessary, though it really is incredibly obvious.82.132.213.42 (talk) 15:05, 13 February 2016 (UTC)

You (the IP) are the one with the "rude and highly disruptive behaviour", and should cease and desist. Your only reason so far has been "rm pov, unencyclopaedic content". What is so "unencyclopaedic" about the content? You may find the bits you deleted trivial/obvious, but not everyone will, someone stumbling on the page may know nothing about the book or subject. No one has made an explicit personal attack against you, just a revert. Everyone gets frustrated when they're reverted but unless the edit summary indicates, a revert is not a "personal attack". M∧Ŝc<sup>2</sup>ħεИ<sub>τlk</sub> 08:46, 15 February 2016 (UTC)

It's also possible to track where you are with a visible IP: AS29180 O2-ONLINE-AS Telefonica UK Limited (registered Jun 23, 2003. In principle, IP addresses at the place can be blocked just from the disruptive behavior of one account. M∧Ŝc<sup>2</sup>ħεИ<sub>τlk</sub> 08:50, 15 February 2016 (UTC)

tensor

${\hat {T}}_{j'}^{i'}=(R^{-1})_{i}^{i'}R_{j'}^{j}T_{j}^{i}=R_{j'}^{j}T_{j}^{i}(R^{-1})_{i}^{i'}$

the first equality is directly computing by the above tensor formula, the second just change the order of sum, which is invariant for finite sum, and the righ hand side is equal to $(RTR^{-1})_{j'}^{i'}$, That's why we have

${\hat {T}}=RTR^{-1}.$

Please check, thanks Wttwcl (talk) 03:40, 29 February 2016 (UTC)

I think you have the order reversed. If a contravariant vector is represented by a column matrix, then you are wrong. JRSpriggs (talk) 02:20, 1 March 2016 (UTC)

Userpage

Hey JRSpriggs. You have been around here a long time. I am surprised to see that you Userpage appears to violate the WP:Userpage policy, with all this stuff on your personal views on various political and economic issues. Do you really think that is appropriate? I don't want to get all admin/dramaboard=y about this... Jytdog (talk) 17:15, 11 March 2016 (UTC)

I think this question was considered before at Wikipedia:Miscellany for deletion/User:JRSpriggs. Do you have a new argument? JRSpriggs (talk) 09:12, 12 March 2016 (UTC)

I believe it would help if sources and/or wikilinks were provided that support the statements on the user page. For example, the non-contradiction section is a rewording or restating of a something found in Atlas Shrugged, Chapter Seven I doubt Ayn Rand was the first to say that but what you have seems close enough that you could credit her. --Marc Kupper|talk 04:47, 19 March 2016 (UTC)

The ideas on my user page are mine. While I do not claim originality for most of them, neither am I consciously quoting anyone else. There is no one (not even Ayn Rand) with whom I totally agree. So I do not generally give links because that might be construed as an unqualified endorsement.

Regarding Ayn Rand in particular: Her notion that there is a fallacy of the stolen concept is itself mistaken. What she calls a fallacy (in this case) is merely a specific variety of contradiction. Since it is a contradiction, it must be the product of a false premise or some (other) fallacy. But it is not necessarily the first falsity in the chain of reasoning itself.

Her notion tends to undermine the process of reasoning by preventing people from searching for the true cause of the contradiction. As such it is a very dangerous idea.

Another place where the Objectivists go wrong is conflating the objectivity of legal judgements with the public nature of them. As a result, they insist that government is necessary even though this does not follow from their theory of rights. JRSpriggs (talk) 16:52, 19 March 2016 (UTC)

I responded.

Please look at User_talk:98.195.88.33.98.195.88.33 (talk) 01:00, 30 May 2016 (UTC)

Regarding your edit to Methods of computing square roots. I am aware that your method works and I am not surprised that you can prove that it does. But that does not address the reasons which I and others gave for excluding it from the article. JRSpriggs (talk) 21:02, 30 May 2016 (UTC)