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Cantor at FAC

Hi Iry-Hor, Thank you for volunteering to be my featured article mentor for "Georg Cantor's first set theory article". I look forward to working with you. You have already compiled an excellent list of items for me to start work on. It will take me awhile to get through the entire list, but I will be informing you of my progress and I will continue to do my work at User:RJGray/Sandbox100. —RJGray (talk) 21:34, 14 November 2019 (UTC)

Hi Iry-Hor, Thank you very much for your excellent lists of things that need fixing in the article. I have responded to all items except the ones that can be delayed. I have made responses on my Talk page after each item and implemented them in User:RJGray/Sandbox100. I've enjoyed going back and making the article better. My reasons for wanting to nominate the article for Featured Article go far beyond this one article. I believe that going through the Featured Article process will help me write better Wikipedia articles and this has already started! I was also motivated to read more of the MOS and check out what others have done in Featured Articles. I look forward to more lists of things to fix. —RJGray (talk) 22:55, 4 December 2019 (UTC)

RJGray I think your article is really excellent. You can confidently propose it at FAC now! Write a very short blurb to present it at FAC and go for it. I will support the article and I am sure plenty of other people will do so too. As I said, once this is FA (FAC can take a couple of months so it will be next year), I strongly suggest you propose it at Today's Features Article Candidates.Iry-Hor (talk) 08:34, 5 December 2019 (UTC)

Hi Iry-Hor, That was fast! I didn't realize I was so close to a FA. I was going to ask you for an example blurb, but I've found them myself. For example, I found one that you were involved with at the beginning of Wikipedia:Featured article candidates/Featured log/November 2019#Decipherment of ancient Egyptian scripts. With the holiday season approaching, I'm going to be very busy so I won't have that much time to fix things. I have no idea of what kind of response time they expect on a FAC. Should I wait or go ahead? Of course, I first have to write the blurb. I'm getting ideas now by reading some blurbs and then I have some writing and rewriting to do. Thanks again for the work you have done in making excellent suggestions for the article. —RJGray (talk) 00:02, 6 December 2019 (UTC)

RJGray Yes it was fast because your article was already in great shape ! So a few advises concerning FAC:

• 1) On the FAC blurb: the idea is not so much to summarize the article, but rather to motivate people into reviewing it. Indeed, to pass FAC you need at least an image review, a source review and spot checks, and 3 supports with prose reviews. It happens from time to time that an article fails at FAC for lack of reviews (this is rare but you want to avoid this disappointment)! Thus, your blurb can include, beyond a short non-comprehensive summary, a few sentences about the importance of reviewing the article. For example I observe that FA maths article on wikipedia are very rare: there are less 20 maths-related FA articles on a total of nearly 6000 FA. In other words ~0.3% of all FA articles pertain to maths. This is catastrophically low, especially knowing that FA articles themselves represent ~0.1% of all wikipedia articles.
• 2) Once you have put up the article at FAC, you need to watch for reviews daily or so, because once people have started reviewing the article they will wait for your responses and discussions can ensue. Thus you cannot fail to respond for long times as otherwise the reviews won't be completed and the article will have failed. Thus, if you feel like you will be busy during the upcoming Christmas period and won't be able to respond quickly at FAC, it is better to post the article at FAC in January, i.e. when you are sure that you will be responsive on short time scales.
• 3) The FAC process is long (a couple of months is typical) with short bursts of activities (when someone reviews the article) with periods of nothing in between. This is normal.
• 4) The blurb is crucial after FAC if you want to be candidate at Today's Featured Article. At this point you will need to sit down and write a really good blurb summarizing the article comprehensively with tight constraints on the number of words. We will see this together if you want, once the time comes.Iry-Hor (talk) 13:02, 6 December 2019 (UTC)

Hi Iry-Hor, below is my FAC blurb. I've rewritten it several times and I need feedback on it.

This article is about Cantor's first article on infinite sets, which contains his discovery of two kinds of infinite sets: countable sets and uncountable sets. The members of a countable set, such as the fractions between 0 and 1, can be written as the sequence 1/2, 1/3, 2/3, 1/4, 3/4, … . The members of a uncountable set, such as the real numbers between 0 and 1, cannot be written as a sequence. The significant developments in mathematics that came from the use of countable and uncountable sets justify the importance of this article. Also, it would be good to have another featured article on mathematics: of the nearly 6,000 featured articles, only 18 (about 0.3%) are on mathematics.

This Wikipedia article passed its GA review in August 2018 and its DYK review in December 2018. Since this is my first time nominating an article, I contacted a FAC mentor, Iry-Hor, whose excellent advice led to further improvements. I look forward to more advice that will hopefully lead to a featured article.

Thanks for your help, RJGray (talk) 12:51, 9 January 2020 (UTC)

RJGray Nice blurb, perhaps the sentence "The members of a countable set, such as the fractions between 0 and 1, can be written as the sequence 1/2, 1/3, 2/3, 1/4, 3/4," could make clearer that while the observation on sequences is generally true for countable sets, the precise sequence given refers only to the example, e.g. "The members of a countable set, such as the fractions between 0 and 1, can be written as a sequence, for example 1/2, 1/3, 2/3, 1/4, 3/4,". Also is it not "an uncountable" rather than "a uncountable"? Other than that I think this blurb is quite sufficient for FAC. Iry-Hor (talk) 08:49, 10 January 2020 (UTC)

Hi Iry-Hor, Thanks for spotting the problems with my blurb. Its first paragraph now reads:

This article is about Cantor's first article on infinite sets, which contains his discovery of two kinds of infinite sets: countable sets and uncountable sets. The members of a countable set can be written as a sequence; for example, the fractions between 0 and 1 can be written as the sequence 1/2, 1/3, 2/3, 1/4, 3/4, …   . The members of an uncountable set cannot be written as a sequence; for example, the real numbers between 0 and 1 cannot be written as a sequence. The significant developments in mathematics that came from the use of countable and uncountable sets justify the importance of this article. Also, it would be good to have another featured article on mathematics: of the nearly 6,000 featured articles, only 18 (about 0.3%) are on mathematics. RJGray (talk) 21:22, 11 January 2020 (UTC)

RJGray Nice and good luck at FAC! Let me know when your article is up there so I can support the nomination.Iry-Hor (talk) 08:04, 12 January 2020 (UTC)

Nomination blurb

This article is about Cantor's first article on infinite sets, which contains his discovery of two kinds of infinite sets: countable sets and uncountable sets. The members of a countable set can be written as a sequence; for example, the fractions between 0 and 1 can be written as the sequence 1/2, 1/3, 2/3, 1/4, 3/4, …   . The members of an uncountable set cannot be written as a sequence; for example, the real numbers between 0 and 1 cannot be written as a sequence. The significant developments in mathematics that came from the use of countable and uncountable sets justify the importance of this article. Also, it would be good to have another featured article on mathematics: of the nearly 6,000 featured articles, only 18 (about 0.3%) are on mathematics.

This Wikipedia article passed its GA review in August 2018 and its DYK review in December 2018. Since this is my first time nominating an article, I contacted a FAC mentor, Iry-Hor, whose excellent advice led to further improvements. I look forward to more advice that will hopefully lead to a featured article.

New code

6623 {{FA: number}} {{#expr: 6913498

Minus sign

x − y The 3 − 4; 6 − 7; 5 − 4 ; 5 — 4 ; 5 − 4 ; {{subst:minus}}) − correct encoding of the minus sign "−" is different from all varieties of hyphen "-‐‑", as well as from en-dash "–". To really get a minus sign, use the "minus" character "−" (reachable via selecting "Math and logic" in the drop-down list below the edit box or using {{subst:minus}}) or use the "−" entity. z ${\sqrt {3}},{\sqrt {5}},\dots ,{\sqrt {17}}$

x₁, x₂, x₃, … x₁, x₂, x₃, ... x₁, x₂, x₃, . . . Either the number of intervals generated is finite or infinite. If finite, let (a_L, b_L) be the last interval. If infinite, take the limits a_∞ = lim_n → ∞ a_n and b_∞ = lim_n → ∞ b_n. Since a_n < b_n for all n, either a_∞ = b_∞ or a_∞ < b_∞. Thus, there are three cases to consider:

Case 1: Last interval (a_L, b_L). Real line containing closed interval [a, b] that contains nested open intervals (a_n, b_n) for n = 1 to L. The number y is in (a_L, b_L) and differs from every x_n.

Case 2: a_∞ = b_∞. Real line containing interval [a, b] that contains nested intervals (a_n, b_n) for n = 1 to ∞. These intervals converge to a_∞, which differs from every x_n.

Case 3: a_∞ < b_∞. Real line containing interval [a, b] that contains nested intervals (a_n, b_n) for n = 1 to ∞. These intervals converge to the closed interval [a_∞, b_∞] and every y in [a_∞, b_∞] differs from every x_n.

Photos

US copyright tags: [1]

Cantor:

 Oberwolfach Photo Collection: [2]
   Annotation: From a photo album of the Mathematische Gesellschaft (Hamburg)
   Location:
   Source: [3]
   Photo ID: 10525

Perron:

 Oberwolfach Photo Collection: [4]
   Annotation: ca. 1948
   Location: München
   Author: Jacobs, Konrad (photos provided by Jacobs, Konrad)
   Source: Konrad Jacobs, Erlangen
   Copyright: MFO
   Photo ID: 3261

Fraenkel:

 The David B. Keidan Collection of Digital Images from the Central Zionist Archives (via Harvard University Library)

Weierstrass (31 October 1815 – 19 February 1897):

 Smithsonian: [5]
 Oberwolfach Photo Collection: [6]
   Annotation: From a photo album of the Mathematische Gesellschaft (Hamburg)
   Location:
   Source: [7]
   Photo ID: 10522  

Kronecker:

 Possible Source: Bildarchiv Preussischer Kulturbesitz, Berlin, [8]
 Photographer: Ernst Milster, 1835-1908
 Date taken: circa 1870
 Place taken: Berlin

Dedekind:

   Photo de Richard Dedekind vers 1870
   Date	10 February 2007 (original upload date)
   Source	http://dbeveridge.web.wesleyan.edu/wescourses/2001f/chem160/01/Photo_Gallery_Science/Dedekind/FrameSet.htm
   Author	not found
   Permission
   (Reusing this file)	La photo date de plus de 150 ans (en effet, nous sommes en 2020), elle est dans le domaine public