Talk:Picard horn

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Notability

Is this really notable? Some brief interest in popular media and then nothing. In fact, it seems rather FRINGEy. 94.196.51.165 (talk) 18:39, 3 February 2012 (UTC)[reply]

Brief interest? ~~Please read the article:~~ 129 years since the first discussion of the topic in a peer-reviewed journal by professional mathematicians is not just "brief interest in popular media". Boud (talk) 17:41, 16 February 2013 (UTC)[reply]

Sorry, I struck out a few words in my previous comment because the previous structure of the article made it sound like the space was invented only 8 years ago, and the fact that it's 129 years old is mentioned as a technicality. (Anyone new here should still read the article, of course :) .) So I understand the concern.

I've done a brief, quick restructure of the article so that it first focuses on the main thing: this is one of (maybe the?) oldest known hyperbolic 3-manifolds that can be given a constant curvature. 3-manifolds are an important part of mathematics, independent of any application in cosmology - e.g. see Grigori Perelman. The cosmological application is part of the peer-reviewed scientific literature in a serious journal, but the mathematical object exists independently of that. Boud (talk) 18:29, 16 February 2013 (UTC)[reply]

External links modified (January 2018)

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Proper description

There should be something on the article itself. I still cannot understand this thing. In one place it is described as identification of (x, y, z) with (x + an, y + bm, z) in the upper half plane model, but then how can it have a finite volume if volume grows infinitely with z -> 0? Grunewald and Huntebrinker failed to make it any clearer. They puzzle me with “r ≥ …” thing. Oh, man, why is it “r ≥ …”? How can it have a finite volume then? Why not “r ≤ …”? Tiling space with fundamental domain seems to earn modification of Square tiling honeycomb, but I can see no word about it, so maybe it's my mistake. Is there anywhere, finally, something understandable on topic? OCTAGRAM (talk) 01:21, 11 February 2018 (UTC)[reply]