Talk:Sphere

I'm thinking there is some bug with the new wiki software, I saw the text went away that Zundark is talking about, but couldn't figure out how to bring it back. I'm using internet explorer 5, and had no problems with the old software. Either that, or my dog ate it. <grin> -- BenBaker

There was such a bug on the first day. Should be long gone. For old version, you'll have to wait for the promised http://old.wikipedia.com --Magnus Manske

---

Does anyone have any objections to the following text being added...?

A sphere can also be defined as a sphericon that is based on a polygon approaching a circle.

Proberts2003 19:31, 10 Apr 2004 (UTC)

I do Tosha 00:42, 11 Apr 2004 (UTC)

Which are...? Proberts2003 01:45, 12 Apr 2004 (UTC)

Ok, I think it is not directly relevent, one can mention sphere in sphericon, but not other way arround. (Otherwise you should include in this article ref to all geometric topics) Yet an other thing: yes it can be defined this way but it would be most wierd way to define sphere. Tosha 05:15, 12 Apr 2004 (UTC)

---

The article currently says "water drops (in the absence of gravity) are spheres". I changed this to simply "small water drops are spheres" because photographs of rain show small spheres (see http://www.ems.psu.edu/~fraser/Bad/BadRain.html ). -- DavidCary 23:33, 27 Jun 2004 (UTC)

---

I believe the claim that the topological convention is "the most common" is NPOV, as I believe it's a true statement. (Of course, people who work in the fields using the other definition will feel differently...I don't directly work in either field, so I'm going by my own experience. The topological definition is the only definition I've ever seen or heard; until today I wasn't aware there was another convention.) It would be good if the actual fields of research that use this convention were spelled out. (I honestly have no idea what these are.) I strongly object to the use of the term "geometrical definition" or "geometrical convention", because "geometry" is too broad a word; also, it conflicts with the convention used by differential geometers, who most certainly consider themselves to study "geometry". Revolver 00:08, 12 Jul 2004 (UTC)

Unless someone can provide at least one example of a peer-reviewed mathematical paper that uses the term "n-sphere" to mean (n-1)-sphere, then I'm going to remove all this stuff about different conventions. There is only one convention, as far as I'm aware. --Zundark 09:35, 23 Dec 2004 (UTC)

---

Can we split this up into two sections — Geometry and Topology — as I did for Ball (mathematics)? In the Geometry section have the metric-space definition (locus of points a radius from the center; boundary of a ball), the Eulcidean examples, the current Equations subsection, and all that jazz; and under Topology have

A sphere is any space homeomorphic to the Euclidean sphere described above under Geometry.

, definition of n-sphere, the fact that the boundary of a ball is a sphere one dimension down (for n>0), and definitions of homology sphere. —msh210 21:17, 27 Oct 2004 (UTC)

---

the prove that a n-sphere is compact is not complete?

• needs why complement has only innerpoints
• why is it bounded?? (maybe due it's definition <math>S^n = \{ x \epsilon R^{n+1} |d(x,0) = 1\}<math>)

Split article?

Currently the material on n-spheres is split between this article and hypersphere. The situation is somewhat unsatisfactory. I propose separating the material along logical lines

• the sphere article should focus the ordinary 2-sphere in Euclidean 3-space. This is probably what people expect when they type sphere into the search box.
• the n-sphere article should discuss the general case, with sections on both geometry and topology. We can have a redirect from hypersphere to there (I prefer it this way since the term hypersphere is not in common usage in mathematics).

I'm happy to do this split if no one objects. Comments? -- Fropuff 02:29, 2005 Apr 16 (UTC)

Iff sphere has a link to n-sphere at its top (not just Template:Tl), I agree. That is, it should say something like For higher-dimensional spheres in mathematics, see n-sphere; for other spheres see Sphere (disambiguation). —msh210 13:50, 17 Apr 2005 (UTC)