Wikipedia:Articles for deletion/Hyperbolic coordinates

The following discussion is an archived debate of the proposed deletion of the article below. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.

The result was keep. No arguments for deletion aside from the nominator. The issue of merging, redirecting, renaming, or what have you can be discussed on the article's talk page. (non-admin closure) Ron Ritzman (talk) 00:34, 12 June 2010 (UTC)[reply]

Hyperbolic coordinates

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Long standing unreferenced tag and a search did not produce anything to support the material. The term itself seems to be notable but as a coordinate system for hyperbolic space unrelated to the "Quadrant model" mentioned in the article. A search on "Quadrant model"+hyberbolic returned 0 hits. I also found a source that uses the term for coordinates that use hyperbolic functions in the same way that polar coordinates use trigonometric functions. These are unrelated to the material in the article. This has a large number of articles that link to it because it's included in a template for orthogonal coordinate (incorrect since the system in the article is not orthogonal). RDBury (talk) 01:28, 5 June 2010 (UTC)[reply]

Keep. The subject is notable, as the proposer admits. The article is well written and well illustrated. The material at Hyperbolic space is more advanced. The linkage between the articles can be improved. ~~I do not see the phrase "Quadrant model" mentioned in the article.~~ Cuddlyable3 (talk) 19:57, 8 June 2010 (UTC)[reply]

Comment "Quadrant model" is in the title of the first ~~chapter~~section, and "quadrant" is used several times in the article. MKFI (talk) 20:10, 5 June 2010 (UTC) Thanks. Cuddlyable3 (talk) 19:57, 8 June 2010 (UTC)[reply]

Improve - yes, delete - no way. The topic constitutes basic math. (we had to learn how to transform to hyperbolic coordinates in university, but you don't have to trust me - 632 hits on Google books are good enough). Some material there might be WP:OR and thus a cleanup would be appropriate. Materialscientist (talk) 04:26, 6 June 2010 (UTC)[reply]

If this is so then please find a reference for the material in the article and add it. There is such a thing as same term being used to mean different things in different places. A raw Google hit count means nothing if all the hits are for something different or does not support the material. If the material was covered in your university then add your textbook as a reference. As of now I have no evidence that the creator of the article didn't make up a new meaning for a term with another meaning.--RDBury (talk) 05:49, 6 June 2010 (UTC)[reply]

Keep. Subject is canonical. Xxanthippe (talk) 04:12, 6 June 2010 (UTC).[reply]
~~Delete~~ Rewrite from scratch This is unsourced and probably original research (mostly written by a rather unreliable editor with a long history of using unorthodox terminology). It should be deleted unless someone can find at least one reliable source for this use of the term. The many hits for hyperbolic coordinates mentioned above all seem to refer to something else. r.e.b. (talk) 06:39, 6 June 2010 (UTC)[reply]

On 2nd thoughts, "hyperbolic coordinate system" is a legitimate title for an article, so can be kept, but the article needs be completely rewritten from scratch as the current version is original research and not what is usually meant by hyperbolic coordinate system. r.e.b. (talk) 17:08, 6 June 2010 (UTC)[reply]

Merge/redirect to hyperbolic space - There doesn't seem to be much material in this article that isn't already better-described elsewhere. The material not duplicated elsewhere reads like an essay on why the article's editor thinks the coordinate system is handy. Have one of the WP:WPMATH or WP:PHYS editors fold any useful content in and redirect. --Christopher Thomas (talk) 08:03, 6 June 2010 (UTC)[reply]
Comment. The term "hyperbolic coordinates" often refers to geodesic normal coordinates in a hyperbolic space. However, it is also often used in an unrelated way in applied mathematics to refer to coordinate systems like the one described in the article. For instance, the Encyclopedic dictionary of mathematics [1] refers to $x=uv$ , $y=(u^{2}-v^{2})/2$ as a hyperbolic coordinate system. Related coordinate systems introduce hyperbolic functions to parameterize the hyperbolic angle, are closer to the coordinate system defined in the article: see, for instance, [2]. So there are two genera of hyperbolic coordinate systems: those coming from hyperbolic geometry, and those coming from applied mathematics. The article is about hyperbolic coordinates in the latter sense, and a hatnote should be added to indicate the other meaning. Ultimately, if the article is kept, it will need to be completely rewritten from sources to indicate that, even in the second meaning of the term, there are various closely related coordinate systems that are called "hyperbolic", depending on the source. Sławomir Biały (talk) 11:31, 6 June 2010 (UTC)[reply]

The article Parabolic coordinates covers the system described as hyperbolic coordinates in the EDoM. It makes more sense to call them parabolic since the coordinate curves are parabolas. It might makes sense to talk about coordinates defined by the inverse relation

u=xy

,

v=(x^{2}-y^{2})/2

as hyperbolic coordinates but I didn't see this in any of my research.--RDBury (talk) 15:22, 6 June 2010 (UTC)[reply]

Well, in EDoM "parabolic coordinates" refer to the inverse coordinate system. This only further demonstrates my point: even in my latter sense, the terminology is not canonical but clearly refer to a collection of very closely related coordinate systems. Sławomir Biały (talk) 12:42, 11 June 2010 (UTC)[reply]

Keep but throw away the OR. Merging into hyperbolic space makes little sense: it's just a coordinate system, so unless you define a metric it doesn't tell you which kind of space it is. "Coordinates that use hyperbolic functions in the same way that polar coordinates use trigonometric functions" are the same as those described here, except for a 45°-rotation and a √2-scaling. (Just set x′ = x cos(45°) + y sin(45°), y′ = −x sin(45°) + y cos(45°) and substitute the expression for x and y given at the end of the lead to see it.) A. di M. (talk) 13:59, 6 June 2010 (UTC)[reply]

There are no references in the article so how can it be determined what is not OR? If there was anything in the article that I could substantiate then I wouldn't have done the AfD. Also, the coordinate curves for the coordinates defined similarly to polar coordinates are hyperbolas instead of circles, so they are not rotationally equivalent.--RDBury (talk) 15:36, 6 June 2010 (UTC)[reply]

You didn't get the point: in order to define coordinates such that x = a coshφ, y = a sinhφ, you have to pick an x- and a y-axis first, and if you pick axes which are rotated by 45° w.r.t. mine, you get the same coordinate system I would get if I used the formulas in the article. (Essentially, you use x and y to refer to the axes of the hyperbolas and I use them to refer to their asymptotes.) A. di M. (talk) 16:00, 6 June 2010 (UTC)[reply]

I misinterpreted what you were saying the first time but I see what you were getting at now. But we still need a reference for the coordinates as given in the article. I'll try to find where I saw the system I described earlier; maybe it can be used as the basis for a rewrite.--RDBury (talk) 16:28, 6 June 2010 (UTC)[reply]

It's here.--RDBury (talk) 16:37, 6 June 2010 (UTC)[reply]

If it were edited so to use the x = a coshφ, y = a sinhφ definition (or whatever name for a and φ), would you still object to the existence of the article? A. di M. (talk) 13:19, 7 June 2010 (UTC)[reply]

My objective is to remove unreferenced material, so if the article is rewritten based on a reliable source it's fine with me.--RDBury (talk) 04:53, 8 June 2010 (UTC)[reply]

Keep Needs cleanup not deletion, as others have stated. --Falcorian ^(talk) 17:54, 6 June 2010 (UTC)[reply]

Comment: I do not see why this article is in Category:Hyperbolic geometry. As far as I can tell they only have the word "hyperbolic" in common. This is a coordinate system for a presumptively Euclidean space. Thus the suggestion that it be merged in to Hyperbolic space makes no sense. JRSpriggs (talk) 18:11, 6 June 2010 (UTC)[reply]

Keep and rename to Hyperbolic coordinate system (as per Cartesian coordinate system, Polar coordinate system, Elliptic coordinate system). Article describes a system of co-ordinates in 2-D Euclidean space and is only tangentially related to hyperbolic space and hyperbolic geometry. Gandalf61 (talk) 09:06, 7 June 2010 (UTC)[reply]
Comment. I agree with Gandalf61. Xxanthippe (talk) 09:45, 7 June 2010 (UTC).[reply]
Definite keep, possible rename. 01:11, 8 June 2010 (UTC)
Keep. On the basis that Hyperbolic coordinates is a legitimate title. The article has been cleaned up over the past week with refs. added. AWHS (talk) 07:34, 11 June 2010 (UTC)[reply]

The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.