| Revision as of 20:51, 23 February 2020 editDeFacto (talk | contribs)Extended confirmed users43,939 editsm Reverted 1 edit by Johnuniq (talk) to last revision by TakuyaMurata (TW)Tag: Undo← Previous edit | Revision as of 21:02, 23 February 2020 edit undoDavid Eppstein (talk | contribs)Autopatrolled, Administrators226,152 edits Undid revision 942297878 by DeFacto (talk) unexplained removal of project-relevant informationTag: UndoNext edit → | ||
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| I only had a brief exposure to differential geometry, but I firmly believe that the notion that we cannot represent a ] as a matrix when it is a ] on each tangent space instead of a linear transformation thereof is completely wrong, especially absent actual reliable sources for that view. See ] for my full argument on that front. Pinging {{ping|D.Lazard|Joel B. Lewis|Slawekb|RDBury}} among others.--] ] 08:33, 19 February 2020 (UTC) | I only had a brief exposure to differential geometry, but I firmly believe that the notion that we cannot represent a ] as a matrix when it is a ] on each tangent space instead of a linear transformation thereof is completely wrong, especially absent actual reliable sources for that view. See ] for my full argument on that front. Pinging {{ping|D.Lazard|Joel B. Lewis|Slawekb|RDBury}} among others.--] ] 08:33, 19 February 2020 (UTC) | ||
| == Boris Tsirelson == | |||
| Some very bad news regarding ] is at ]. An IP has already added the information to the article, citing the talk page as a reference. This needs sensitive handling that is out of my reach. The IP has posted on ]. I'm hoping that people here will be able to locate a reliable source. ] (]) 08:23, 23 February 2020 (UTC) | |||
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See also: Using Misplaced Pages for mathematics self-study Why are Misplaced Pages mathematics articles so abstract? Abstraction is a fundamental part of mathematics. Even the concept of a number is an abstraction. Comprehensive articles may be forced to use abstract language because that language is the only language available to give a correct and thorough description of their topic. Because of this, some parts of some articles may not be accessible to readers without a lot of mathematical background. If you believe that an article is overly abstract, then please leave a detailed comment on the talk page. If you can provide a more down-to-earth exposition, then you are welcome to add that to the article. Why don't Misplaced Pages's mathematics articles define or link all of the terms they use? Sometimes editors leave out definitions or links that they believe will distract the reader. If you believe that a mathematics article would be more clear with an additional definition or link, please add to the article. If you are not able to do so yourself, ask for assistance on the article's talk page. Why don't many mathematics articles start with a definition? We try to make mathematics articles as accessible to the largest likely audience as possible. In order to achieve this, often an intuitive explanation of something precedes a rigorous definition. The first few paragraphs of an article (called the lead) are supposed to provide an accessible summary of the article appropriate to the target audience. Depending on the target audience, it may or may not be appropriate to include any formal details in the lead, and these are often put into a dedicated section of the article. If you believe that the article would benefit from having more formal details in the lead, please add them or discuss the matter on the article's talk page. Why don't mathematics articles include lists of prerequisites? A well-written article should establish its context well enough that it does not need a separate list of prerequisites. Furthermore, directly addressing the reader breaks Misplaced Pages's encyclopedic tone. If you are unable to determine an article's context and prerequisites, please ask for help on the talk page. Why are Misplaced Pages's mathematics articles so hard to read? We strive to make our articles comprehensive, technically correct and easy to read. Sometimes it is difficult to achieve all three. If you have trouble understanding an article, please post a specific question on the article's talk page. Why don't math pages rely more on helpful YouTube videos and media coverage of mathematical issues? Mathematical content of YouTube videos is often unreliable (though some may be useful for pedagogical purposes rather than as references). Media reports are typically sensationalistic. This is why they are generally avoided. |
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Clockwise and counterclockwise on the Riemann sphere
In this image of the Riemann sphere, going counterclockwise around corresponds to going clockwise around it in the usual way of depicting the plane. Should this reversal of orientation be considered a problem? Michael Hardy (talk) 20:54, 31 January 2020 (UTC)
corresponds to going clockwise around it in the usual way of depicting the plane. Should this reversal of orientation be considered a problem? - Right, the sphere is folded so that the inside is the usual plane. It would be better with i and -i switched. (Also the fonts are quite ugly.) --JBL (talk) 23:31, 31 January 2020 (UTC)
- @JBL: If you swap i with −i it would no longer be a stereographic projection of Argand's plane onto a sphere. At least not in the most obvious configuration. The resulting sphere would be an image of a stereographic projection to a sphere tangens from 'below', then rotated by 180° around its (real 1) -- (real −1) diameter. I'm afraid it's much harder for average reader to understand the plane-to-sphere correspondence in this case than in the one depicted above. --CiaPan (talk) 23:52, 31 January 2020 (UTC)
- @CiaPan: If you swap and and leave where they are, then that fixes the reversal-of-orientation problem and if the Argand plane is parallel to the plane containing and the center of projection is the point labeled on the sphere, then you still have an ordinary stereogrpahic projection. Michael Hardy (talk) 04:19, 5 February 2020 (UTC)
- @JBL: If you swap i with −i it would no longer be a stereographic projection of Argand's plane onto a sphere. At least not in the most obvious configuration. The resulting sphere would be an image of a stereographic projection to a sphere tangens from 'below', then rotated by 180° around its (real 1) -- (real −1) diameter. I'm afraid it's much harder for average reader to understand the plane-to-sphere correspondence in this case than in the one depicted above. --CiaPan (talk) 23:52, 31 January 2020 (UTC)
and 
and leave 
where they are, then that fixes the reversal-of-orientation problem and if the Argand plane is parallel to the plane containing The biggest problem with the font is that hyphens appear where minus signs should be:
Michael Hardy (talk) 06:12, 1 February 2020 (UTC)
- @Michael Hardy: Fixed. --CiaPan (talk) 16:04, 3 February 2020 (UTC)
Or instead of interchanging one could interchange and Michael Hardy (talk) 06:16, 1 February 2020 (UTC)
one could interchange 
Spam article on possibly notable topic
Draft:Word-representable graph was written by an editor who is a name match for the claimed inventor of the term, whose research also dominates the references. Is this actually a valid topic, or is it vanity spam? Guy (help!) 09:38, 5 February 2020 (UTC)
- I don't recognize it. But that doesn't mean it doesn't exist. — Arthur Rubin (talk) 09:47, 5 February 2020 (UTC)
- This is a real topic and Kitaev is a real mathematician. It is fairly new (introduced in the last 15 or so years) and Kitaev has been heavily involved in studying and promoting it (along with a varied group of coauthors), but glancing through MathSciNet I see a dozen or more papers about this topic in non-spam journals by sets of authors that do not include Kitaev. --JBL (talk) 12:44, 5 February 2020 (UTC)
- (Probably I should give a COI notice that Kitaev wrote a letter of recommendation for me 10 years ago when I applied to post-docs, though we haven't had significant contact since.) --JBL (talk) 12:45, 5 February 2020 (UTC)
- I really don’t think it’s a spam. It is actually quite nice that the article is written by the originator of the subject, since that person must know the best. Of course, we have to watch out for a self-promotion but as far as I can tell that’s not an issue here. (It’s only an issue if the topic is fringe; i.e., not something studied in the mainstream mathematics community.) —- Taku (talk) 20:26, 5 February 2020 (UTC)
- Not spam, but very new topic (mostly developed in the last five years) with limited literature as a result. It's not WP:FRINGE, but probably not mature or well-cited enough to be considered WP-notable as an article subject yet. — MarkH21 20:48, 5 February 2020 (UTC)
- (Cf. User talk:S. Kitaev#Word-representable graph moved to draftspace.) Given my mathematical background, I really cannot tell whether the topic is too new for Misplaced Pages (e.g., in computing, 5-10 years might be long enough for encyclopedic treatment). Maybe some other editors in the project can weight in? —- Taku (talk) 19:39, 11 February 2020 (UTC)
- I am somewhat surprised at it being labeled "too new" -- I mean, it is fairly new, but there seems to be an established literature around it, and Kitaev has written a book on the topic. The COI aspect is of the kind that doesn't bother me, personally, much (though YMMV) -- we have a legitimate researcher writing about their legitimate research. I personally would have just cleaned out the most over-the-top bits (e.g., the bibliography of papers, which is certainly not maintainable long-term) and let it live in mainspace. --JBL (talk) 00:02, 12 February 2020 (UTC)
- There’s little literature on the subject independent from Kitaev though. — MarkH21 04:21, 12 February 2020 (UTC)
- Like I said, I went through MathSciNet and (filtering out false positives) there are a dozen papers on the topic that do not have him as an author. For my taste, that's well over the "is this a real thing?" line (though again YMMV). --JBL (talk) 14:28, 12 February 2020 (UTC)
- There’s little literature on the subject independent from Kitaev though. — MarkH21 04:21, 12 February 2020 (UTC)
- I am somewhat surprised at it being labeled "too new" -- I mean, it is fairly new, but there seems to be an established literature around it, and Kitaev has written a book on the topic. The COI aspect is of the kind that doesn't bother me, personally, much (though YMMV) -- we have a legitimate researcher writing about their legitimate research. I personally would have just cleaned out the most over-the-top bits (e.g., the bibliography of papers, which is certainly not maintainable long-term) and let it live in mainspace. --JBL (talk) 00:02, 12 February 2020 (UTC)
Idea for new community workspace
Hi. I would like to create some kind of collaborative workspace where coordinators or members of various WikiProjects would gather and provide updates and information on what is going on at each wikiproject, i.e. regarding their latest efforts, projects, and where interested editors can get involved. For those of you at this very active WikiProject, your input would be very helpful, so I wanted to get your input on whether you'd be interested in helping me to make this happen.
we are discussing this proposal right now at:
* Misplaced Pages:Village pump (proposals)#Idea for new community workspace
Please feel free to let me know what you think of this idea, and please let me know your preference, regarding the options above. if you do not see any need for this idea, that is totally fine. However, I think that the majority of editors lack awareness of where the truly active editing is taking place and at which WikiProjects, and I would like to do whatever I can to help make people more aware of where the activity is, what they can do to help, and also which areas of Misplaced Pages offer ideas and efforts that might help them in their own editing activities. Please feel free to let me know.
- Would you be interested in an idea of this nature?
- If so, which option below seems most feasible to you?
- Create a new page/talk page at the existing WikiProject Council, where members of various WikiProject can gather to offer updates, information and ideas on the latest efforts at each of their own WikiProject, such as Misplaced Pages:WikiProject Council/Town Hall.
- Create an entirely new WikiProject with an inclusive name such as
- Create a new collaborative page or forum, but not as a new WIkiProject, i.e. with some name like
- Create a new sub-page in my own userspace, such as User:Sm8900/Town Hall
- Create a subpage at an umbrella-type WikiProject that already covers a broad topical area, such as Misplaced Pages:WikiProject History/Town Hall
thanks. --Sm8900 (talk) 19:03, 9 February 2020 (UTC)
Draft:Derived Noncommutative Algebraic Geometry
A review of this draft is requested. Should it be accepted into article space? Robert McClenon (talk) 22:47, 10 February 2020 (UTC)
- Unsure if it merits its own article at the moment, but merging it to Derived algebraic geometry (which is currently underdeveloped) is a viable option. — MarkH21 00:32, 11 February 2020 (UTC)
- I agree the merger is a better option. My Google search tells that this is the derived version of noncommutative algebraic geometry and so merged with that article makes more sense. —- Taku (talk) 07:18, 11 February 2020 (UTC)
- Hi everyone, I saw the DNCAG article was rejected because it was labelled as a spinoff of the article on derived algebraic geometry. Although these articles has similar sounding titles, they are distinct subjects. Here's a useful analogy: algebraic geometry is to noncommutative geometry as derived algebraic geometry is to derived noncommutative algebraic geometry. The basic objects considered in these fields are separate. In DNCAG the objects are triangulated categories while in DAG they are derived rings, such as simplicial rings or differential graded algebras. Here's a couple relevant links https://en.wikipedia.org/Noncommutative_geometry#Noncommutative_affine_and_projective_schemes https://en.wikipedia.org/Algebraic_geometry Is it fine if I resubmit this article and not have it declined because of the discussed reasons above? Is there anything you'd like me to add to the DAG article to try and differentiate the two subjects even further? Wundzer (talk • contribs) 19:17, 11 February 2020 (UTC)
- Also, here are some plans for the article which further differentiates it from the DAG article: It will include discussions of fourier mukai transforms, deformations of FM transforms, deformations of abelian categories, derived categories of singularities and matrix factorizations. Moreover, check out my comments on the talk page of the DAG page. I've listed out some information for how the article could be expanded, without having a full on merger
- Wundzer, what do you feel about the merger with Noncommutative algebraic geometry? If I remember right, thinking that a category (or higher one) is a type of noncommuattive space is central to NAG. So, the merger with the article makes more sense. (On the other hand, the merger with the DAG article is very bad idea). If a length becomes an issue, we can always spin-off the DNCAG portion later. -- Taku (talk) 00:57, 13 February 2020 (UTC)
- TakuyaMurata, that's not a bad idea, but let's wait a week or so. I'll go ahead and add more to the DNCAG article and then we can make a decision then. I agree they are similar subjects, Rosenberg has a non-commutative geometry based on abelian categories. Moreover, -- User:Wundzer (talk)
- Certainly. —- Taku (talk) 23:23, 13 February 2020 (UTC)
- I have risen a potential issue with the article title (i.e., not completely sure if DNAG is the common name) at Draft_talk:Derived_noncommutative_algebraic_geometry#Main reference needed. -- Taku (talk) 00:31, 21 February 2020 (UTC)
- TakuyaMurata, that's not a bad idea, but let's wait a week or so. I'll go ahead and add more to the DNCAG article and then we can make a decision then. I agree they are similar subjects, Rosenberg has a non-commutative geometry based on abelian categories. Moreover, -- User:Wundzer (talk)
- Wundzer, what do you feel about the merger with Noncommutative algebraic geometry? If I remember right, thinking that a category (or higher one) is a type of noncommuattive space is central to NAG. So, the merger with the article makes more sense. (On the other hand, the merger with the DAG article is very bad idea). If a length becomes an issue, we can always spin-off the DNCAG portion later. -- Taku (talk) 00:57, 13 February 2020 (UTC)
Hey, does anyone know how to embed tikz diagrams into wikipedia? I want to draw out the diagram for TR4 in https://arxiv.org/pdf/math/0302304.pdf, but using the objects in the construction part of the article.Wundzer (talk) 20:06, 20 February 2020 (UTC)
- @Wundzer: You can upload the diagram as an image, since there is no tikz-cd support in WP right now. Instructions are here, just ignore the xy-pic step. — MarkH21 20:46, 20 February 2020 (UTC)
Name change: non-standard -> nonstandard_nonstandard-2020-02-14T04:54:00.000Z">
We are discussing here whether to remove the hyphen in nonstandard analysis, in line with most of the current literature on the topic. Please weigh in. --Jordan Mitchell Barrett (talk) 04:54, 14 February 2020 (UTC)_nonstandard"> _nonstandard">
- Seems we've reached a consensus to change. If you see any uses of the word "non-standard" in reference to nonstandard analysis or the use of ultrapower methods, please change these to "nonstandard". --Jordan Mitchell Barrett (talk) 06:01, 15 February 2020 (UTC)
- Need a bit of help performing the move - I've done the main page and fixed up that page's content, but still need to do this talk page, everything in this category, etc... — Preceding unsigned comment added by Jordan Mitchell Barrett (talk • contribs) 06:48, 15 February 2020 (UTC)
Page proposal - homotopy classification of fiber bundles
There should be a page describing the homotopy classification of fiber bundles. This could include the classification of vector bundles, sphere bundles over spheres, and complex line bundles. This topic motivates a lot of other topics in mathematics, such as characteristic classes and stacks. What are people's thoughts? Wundzer (talk) 22:54, 15 February 2020 (UTC)
- Isn’t that what a classifying space (or its variant) is for? Do you have a proposed name for the article you’re proposing? —- Taku (talk) 23:07, 15 February 2020 (UTC)
- Whoops, this will work. Thanks for the heads up. This section can be deleted. Wundzer (talk) 18:33, 17 February 2020 (UTC)
One of your project's articles has been selected for improvement!
 Hello, |
Matrix representation of tensors
This article is so problematic (in my view) that deletion is warranted, hence the AfD. If someone with better knowledge of this subject can rescue the article, then I'll withdraw my AfD.
I only had a brief exposure to differential geometry, but I firmly believe that the notion that we cannot represent a metric tensor as a matrix when it is a bilinear form on each tangent space instead of a linear transformation thereof is completely wrong, especially absent actual reliable sources for that view. See Misplaced Pages:Articles for deletion/Matrix representation of tensors for my full argument on that front. Pinging @D.Lazard, Joel B. Lewis, Slawekb, and RDBury: among others.--Jasper Deng (talk) 08:33, 19 February 2020 (UTC)
Boris Tsirelson
Some very bad news regarding Boris Tsirelson is at Talk:Boris Tsirelson#Death. An IP has already added the information to the article, citing the talk page as a reference. This needs sensitive handling that is out of my reach. The IP has posted on my talk. I'm hoping that people here will be able to locate a reliable source. Johnuniq (talk) 08:23, 23 February 2020 (UTC)