Wikipedia talk:WikiProject Mathematics

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Mathematics glossaries

Given that Wikipedia:WikiProject Glossaries is inactive, do we want to do anything with the mathematics and logic glossaries? A few possibilities:

1. These glossaries are a bad use of our editors' time. Remove them from this WikiProject.
2. These glossaries are not very important to us, but they should still all be added to this WikiProject as low-priority.
3. It is useful to have some glossaries, and we should clean up the existing organization insofar as it is insufficient and spend some editor time improving these.
4. Glossaries are be an important way for us to organize our articles, and we should spend significant time on them.
5. Some of these glossaries are important and we should spend time on them, and others are really not important and we can safely ignore them.

I'm wondering where others stand on this. I would consider myself either a 2er or a 3er. If some of you are 3ers or 4ers, I can propose a clean-up to the existing organization. Also note the existence of Category:Outlines of mathematics and logic and Category:Mathematics-related lists. Mathwriter2718 (talk) 00:57, 22 July 2024 (UTC)

I definitely find some of the glossaries to be important, for at least two reasons. First and most importantly, they provide wikilink targets for terminology that may not have or deserve its own separate article. But also, by putting the terminology for a subfield in a single place, they give readers a broad overview of the terminology and can be a helpful warning about certain pieces of ambiguous terminology. In particular I think those justifications are all valid for the glossary I have put the most effort into, glossary of graph theory. But I don't think your questions can be answered as you have formulated them, at least not by me, because I don't have the comprehensive knowledge about all our glossaries that would enable me to answer universally-quantified questions about them.

As for wastes of editors' time: I think you are wasting your time casting around for content to destroy. Find something more constructive to do. —David Eppstein (talk) 01:14, 22 July 2024 (UTC)

@David Eppstein I am sorry that I gave off the impression that I am "casting around for content to destroy". To be honest, I am kind of shocked by your accusation, and I don't really know where it is coming from. Mathwriter2718 (talk) 02:28, 22 July 2024 (UTC)

Perhaps you found my inclusion of position 1 offensive, but I do not support position 1, and position 1 does not call for "destroying content". Mathwriter2718 (talk) 02:30, 22 July 2024 (UTC)

After looking again at @Jacobolus's comment, maybe I was unclear: by 1's "remove from this project", I meant "remove the WPM template from their talk page", not delete the page. I only brought this up because some of the math glossary pages are do not have the WPM template, and I was trying to ask if this was intentional before I went ahead and added them to WPM. That was what really prompted me to make this post. Mathwriter2718 (talk) 02:57, 22 July 2024 (UTC)

There is no reason to remove the WPM template. If it is missing from one or another of these pages feel free to add it. –jacobolus (t) 08:35, 22 July 2024 (UTC)

Hey, everyone here is a volunteer. We should respect what other people choose to spend their time on, even if it's not interesting to us. Mathwriter2718 was not proposing the deletion of any content, merely trying to get a sense whether this WikiProject wanted to adopt some additional pages. -- Beland (talk) 17:06, 7 August 2024 (UTC)

These glossary pages all have very few page views. Feel free to work on improving them if you want to, or else leave them alone. They aren't particularly important to Wikipedia as a project or WPM just because they are so rarely seen. But they also aren't hurting anything. There's no reason to remove them. –jacobolus (t) 02:20, 22 July 2024 (UTC)

As someone who edits the glossaries articles a lot, I think the glossaries should have a place in Wikipedia. To add to what David said, the glossaries often contain red links and red links are useful and important. I don’t know about view counts of the glossaries but they shouldn’t matter much; in fact, in Wikipedia, we don’t pursue views or likes (gasp) and that should be a good thing. What I am less sure about are lists of topics or outline articles; they seem to cover essentially the same ground as that by the glossaries. So, we can argue there is some redundancy, which itself is not a problem but the less redundant the content is the easier we can maintain it. —- Taku (talk) 06:25, 22 July 2024 (UTC)

I had a look on category:Glossaries of mathematics. Most of them are glossaries of "terminology of some area of mathematics". Such glossaries are very useful, especially for areas that have a large terminology that is commonly used without being redefined and for areas, such as graph theory, where the number of variants make correct linking difficult. Some general glossaries seem also essential, such as Glossary of mathematical jargon and Glossary of mathematical symbols, for which many individual entries cannot be the subject of specific articles. The only mathematical glossary that is problematic seems Glossary of areas of mathematics, per WP:INDISCRIMINATE, and also because the linear order of a glossary hides the complex graph of the relationships between areas of mathematics, better renderes with categories.

On the other hand, most articles in Category:Outlines of mathematics and logic are misleading because they oversimplify their object and give a biased information by omitting important aspects and giving too much importance to minor aspects. IMO, most articles entitled "Outline of someAreaOfMathematics" or "List of topics in someAreaOfMathematics" should be transformed into a redirect to someAreaOfMathematics. D.Lazard (talk) 09:50, 22 July 2024 (UTC)

Thanks for mentioning Category:Glossaries of mathematics, I hadn't seen that. I updated Wikipedia:Contents/Glossaries/Mathematics and logic to be consistent with it. I went ahead and added all of the pages in that category (that weren't already) to WPM.

It seems to me like the following glossaries ought to exist (but don't currently):

• Analysis (real and complex),
• Combinatorics,
• Differential equations and dynamics (which would include both ODE and PDE),
• Geometric topology,
• Logic (or model theory, if logic overlaps too much with set theory, for which a glossary already exists),
• Number theory.

Mathwriter2718 (talk) 13:23, 22 July 2024 (UTC)

We have Glossary of algebraic topology, which should cover geometric topology. On the other hand, I am quite surprised to find out that we don’t have glossary of number theory and glossary of complex analysis (we do have Glossary of arithmetic and diophantine geometry, but that one would arguably have a limited scope.) —- Taku (talk) 15:10, 22 July 2024 (UTC)

I have just started glossary of real and complex analysis; seems no-brainer. —- Taku (talk) 07:52, 23 July 2024 (UTC)

Excellent, thank you. That really is a no-brainer, as is Glossary of number theory, which I will start today. In my opinion, Glossary of algebraic topology should be renamed to Glossary of algebraic and geometric topology and geometric topology terms should be added to it. I also think it would make sense to rename Glossary of topology to Glossary of general topology or Glossary of point-set topology. Mathwriter2718 (talk) 11:24, 23 July 2024 (UTC)

Why not make Glossary of geometric topology a separate article? -- Shmuel (Seymour J.) Metz Username:Chatul (talk) 13:04, 23 July 2024 (UTC)

I would support this too. I don't feel strongly either way. Mathwriter2718 (talk) 13:18, 23 July 2024 (UTC)

I personally feel geometric topology is a subfield of algebraic topology, and it’s usually easier to maintain fewer articles. But I don’t have a strong opinion on the matter. I second on a move of glossary of topology; in fact, I will just go ahead and do now. —- Taku (talk) 14:12, 23 July 2024 (UTC)

I definitely disagree that geometric topology is a subfield of algebraic topology. Mathwriter2718 (talk) 14:16, 23 July 2024 (UTC)

Well, it probably depends on how you define algebraic topology. Do you consider Poincaré conjecture belongs to algebraic topology or geometric topology? For me, it’s a result in algebraic topology more specifically in geometric topology. I do not see it does not belong to algebraic topology; that’s weird (weird because Poincaré is a sort of results you tell laypersons when you explain algebraic topology). That’s what I mean by a subfield. Taku (talk) 15:41, 23 July 2024 (UTC)

RfD

Can somebody help me list a new redirect for discussion about Elongated tetragonal disphenoid? There is a discussion the redirect should be deleted, but the result is the wrong venue. Now I have no idea how do I handle this technical thing.

• Wikipedia:Articles for deletion/Elongated tetragonal disphenoid

Dedhert.Jr (talk) 08:21, 1 August 2024 (UTC)

If you install the Twinkle tool (see instructions at this link), it allows you to conveniently create an RfD (and any other deletion discussion). Once installed, go to the redirect page, press on 'TW' next to the star and click on XfD. You can then input your reasoning and submit the RfD; Twinkle will create the discussion for you. Sgubaldo (talk) 10:07, 1 August 2024 (UTC)

Are there other ways to propose RfD instead of using Twinkle? This tool seems risky. Dedhert.Jr (talk) 04:13, 2 August 2024 (UTC)

Have you seen WP:RFDHOWTO? Mathwriter2718 (talk) 12:00, 2 August 2024 (UTC)

I have seen that, but still got stuck. This is unlike WP:AfD inputting which article you would like to delete. The RfD, according to me, is somewhat the next harder level technical to propose an article. Dedhert.Jr (talk) 15:40, 4 August 2024 (UTC)

I listed it at Redirects for discussion here. Felix QW (talk) 08:25, 7 August 2024 (UTC)

Many thanks. Dedhert.Jr (talk) 03:56, 8 August 2024 (UTC)

Optimisation under uncertainty

I've noticed that we have a few articles related to it (Stochastic optimization, Robust optimization) but there is no article which gives a general overview of the topic. Do you think it would make sense to create it? Would it be better to describe methods like chance constraints programming in a that article or to add them to Stochastic optimization? Alaexis_¿question? 16:01, 3 August 2024 (UTC)

I've created an article about chance constrained programming for a start, I'd be grateful if someone could review it. Alaexis_¿question? 07:23, 10 August 2024 (UTC)

Presently, it is too abstract to make sense to me. Please, add at least one simple example and show how it fits the abstract model. JRSpriggs (talk) 12:54, 10 August 2024 (UTC)

Thanks for the feedback, I'll try to add something over the next few days. Alaexis_¿question? 19:46, 10 August 2024 (UTC)

Cleaned up the article 7

Hi, I just went through the mathematical facts on the article 7 with a bit of a blowtorch and removed a lot of trivial, not well connected to the number 7, or inaccessible mathematical facts about the number. I might go through other articles like this but I wanted to first get feedback here. Allan Nonymous (talk) 15:55, 5 August 2024 (UTC)

Looks good. A lot of our number articles have been accumulating a similar amount of cruft, thanks in part to the efforts of one editor in particular. One small critique: I would be inclined to restore the fact about 7 being the most likely roll for a pair of six sided dice. Tito Omburo (talk) 16:05, 5 August 2024 (UTC)

Definitely a good fact to restore. Mathwriter2718 (talk) 16:32, 5 August 2024 (UTC)

It's still there. XOR'easter (talk) 16:43, 5 August 2024 (UTC)

That looks like a good trim overall. I might quibble on the details later, but it seems mostly fine. XOR'easter (talk) 17:43, 5 August 2024 (UTC)

An edit removing that much material deserves a thorough review to ensure there is not any rescueable content that was deleted. Maybe we can even update the guidelines to specify what kind of facts are considered interesting enough to include and what is cruft, considering how much work there is to do on the number pages. @Dedhert.Jr asked about such a guideline in Wikipedia_talk:WikiProject_Numbers#Interesting_properties. Mathwriter2718 (talk) 17:51, 5 August 2024 (UTC)

I 100% agree, feel free to go in and add back (in a more clear and concise way) some of the facts deleted if there is a consensus to do so. Allan Nonymous (talk) 19:34, 5 August 2024 (UTC)

I, for one, am happy to see cruft removed from our number articles. I was working on that for a while but kind of gave up after Wikipedia:Articles for deletion/198 (number) (2nd nomination) last year. But although many of the listed mathematical properties in these articles are crufty and uninteresting, I think a bigger cause of cruft is the use of numbers as identifiers rather than for their numeric value (for instance as numbers of highways, bus lines, etc), which to my mind should go on separate disambiguation pages rather than on articles about the numbers themselves. —David Eppstein (talk) 19:42, 5 August 2024 (UTC)

Note: following the positive feedback here, I have gone through other number articles, especially (shudders) 744 (Number). Frankly, I think its fine time we write up a WP:NOTOEIS policy to prevent so many of these "xth number with y property" entries. Allan Nonymous (talk) 19:46, 5 August 2024 (UTC)

Perhaps it is time for WP:NOTOEIS, though I don't have enough experience with number pages to know if this is actually necessary.

The most obvious content for removal is of the form "number x is associated with number y, and number y has property a" on pages for number x. See https://en.wikipedia.org/w/index.php?title=744_%28number%29&diff=1238550872&oldid=1230509719 for an example. Even if both statements are valid on their own, the fact that number y has property a should still typically not be on the page for number x.

Statements of the form "number x has property a" are, in my opinion, valid if and only if property a is sufficiently interesting, as are statements of the form "number x is the yth number with property a". It's not clear to me that mentioning that it is the yth is usually any more helpful than just saying "number x has property a", unless y is very small. For example, the page for 45 should probably say that 45 is a triangle number, but I can't convince myself that saying it is the 9th triangle number is any more helpful. On the other hand, maybe the page for 3 should say that 3 is the first non-even prime. Mathwriter2718 (talk) 20:04, 5 August 2024 (UTC)

Perhaps a guideline might say that OEIS is a reliable source but it cannot be used to establish notability of a fact. Mathwriter2718 (talk) 20:09, 5 August 2024 (UTC)

My personal inclination is that a number appearing in an OEIS entry is only worth mentioning if the sequence is "nice", "core" (of central importance to some topic), or "hard" (which often means that it comes from an unsolved problem). Because the source is reliable but intentionally rather indiscriminate, we should focus our attention on the subset of it that is marked as more interesting than the rest. Or, in other words, we should follow the source when it comes to emphasis. XOR'easter (talk) 20:17, 5 August 2024 (UTC)

We might get almost the same effect by only mentioning properties or sequences that have bluelinked Wikipedia articles. —David Eppstein (talk) 20:24, 5 August 2024 (UTC)

Yes, that sounds plausible. XOR'easter (talk) 20:37, 5 August 2024 (UTC)

I think OEIS needs to be treated with caution, essentially as a WP:PRIMARY source. Tito Omburo (talk) 20:54, 5 August 2024 (UTC)

See the discussion now at Wikipedia talk:What Wikipedia is not#WP:NOTOEIS. XOR'easter (talk) 21:05, 5 August 2024 (UTC)

Regarding this problem being related to OEIS, do we have to check again whether OEIS is questionably reliable? This was discussed when I was reviewing 69 (number) to become GA. Maybe, just maybe, just in case, some points of view can be included to support the new additional guidelines we have discussed right now. Dedhert.Jr (talk) 02:12, 6 August 2024 (UTC)

In my view, OEIS is entirely reliable; its edits go through a very strict hierarchy of multiple reviewers, much like a peer-reviewed journal. This process has led it to be much less error-prone than many other sources such as Wikipedia or (worse) MathWorld. What it does not provide is depth of coverage of individual numbers, such as would be needed for WP:GNG-based notability. And because the choice to include a sequence is WP:ROUTINE, it does not tell us much about the notability of individual sequences. —David Eppstein (talk) 17:06, 6 August 2024 (UTC)

I agree with this. XOR'easter (talk) 17:26, 6 August 2024 (UTC)

I think OEIS is reliable (though not a good indicator of notability). Mathwriter2718 (talk) 17:28, 6 August 2024 (UTC)

There is a related discussion (also opened by @Allan Nonymous) at Wikipedia_talk:WikiProject_Numbers#Help_remove_WP:CRUFT_on_number_articles!. Mathwriter2718 (talk) 15:39, 7 August 2024 (UTC)

The article 7 has a long but nowhere near complete section (previously titled "History", which I moved to 7 § Numeral shape) about the way the glyph is drawn in various countries and historical periods. This seems off topic or at least out of scope for an article about the number 7 per se. Should there be dedicated articles about individual numerals and the history of their visual representation in various written number systems? (While we are at it, {{Infobox number}} is an egregious waste of space.) –jacobolus (t) 03:37, 6 August 2024 (UTC)

I think it makes sense to have a section about how 7 is drawn in the article for 7. Mathwriter2718 (talk) 10:53, 6 August 2024 (UTC)

If I may stick my nose in here: user @Allan Nonymous seems to be edit warring on a number of number pages. Reviewing the edit history for number one, I see the removal of all interesting and spicey mathematical facts, leaving behind a bland, tasteless and boring section on math. Whatever your views on cruft may be, the reality is that math is widely misunderstood in Western Culture, often taken to be "boring". Most of us here have the opposite experience: we know how interesting, exciting and even mind-boggling it is. To take the numbers articles, and remove everything that is mathematically interesting and exciting from them just reinforces the ugly stereotype that "math is boring". Let's not do this. 67.198.37.16 (talk) 19:06, 7 August 2024 (UTC)

Oh, foo. I now see that some of this is related to the histrionics from User:Radlrb, above, in the discussion about number 1234. While not a fan of histrionics, there are the unresolved questions of "what makes mathematics interesting?" and "how should enthusiastic compilations of facts about numbers be treated in Wikipedia?" For example, looking at the dozens (hundreds?) of articles on Lie algebra theory, we see that they are often extensive compendiums of factoids and trivia, but we have no problem with that content. We enjoy things like Jacques's titilating Tits buildings. But the trivia and factoids added & removed for 1234? Not so much, it seems. Part of me wants to encourage amateur enthusiasts. A different part of me says "take it to youtube if you think it's interesting." Beats me. 67.198.37.16 (talk) 19:56, 7 August 2024 (UTC)

I'm not sure about Lie algebra pages, but I routinely find mathematical articles on Wikipedia that are very short on context, history, and basic explanation but have long lists of obscure trivial formulas etc. I for one would be very happy to see some of that cruft cleaned up and the space used for material that would be reasonably found in a well written survey paper. –jacobolus (t) 02:14, 8 August 2024 (UTC)

Obscure factoids are fine if there exist reliable secondary sources. But for a lot of these number edits, the only source for some property is OEIS, and often it's a "second order" property that requires combining two OEIS entries, or counting the number of things in an OEIS entry. OEIS is a primary source, and this kind of original research is expressly forbidden (and specifically called out at WP:PRIMARY). Tito Omburo (talk) 13:15, 8 August 2024 (UTC)

I agree with you that the most pressing problem is not obscurity but OR. I think the introduction of the term "cruft" to these discussions might have lead us to focus in the wrong direction. Mathwriter2718 (talk) 14:13, 8 August 2024 (UTC)

To take the numbers articles, and remove everything that is mathematically interesting and exciting from them just reinforces the ugly stereotype that "math is boring". Let's not do this. Yep. Please don't throw the baby out with the bathwater. I'm more than happy to go through anything at 1 which is deemed unsuitable but this was GA quality content. Polyamorph (talk) 23:38, 7 August 2024 (UTC)

but this was GA quality content Meh! Still lack of sources. Demoted to C-class per both WP:QUALITY and this assessment project. Dedhert.Jr (talk) 02:30, 8 August 2024 (UTC)

I'm talking about some of the prose I added, not the article as a whole. Polyamorph (talk) 04:33, 8 August 2024 (UTC)

Dynkin diagram dark mode

Dark mode seems to break the {{Dynkin}} template. E.g., . -- Tito Omburo (talk) 18:38, 7 August 2024 (UTC)

Verified both with the dark mode gadget (under gadgets in preferences) and with the dark mode appearance menu item (in Vector2020, the goggle icon in the upper top right). In both cases the yellow dots stay yellow dots but all the lines and annotations become invisible. —David Eppstein (talk) 19:02, 7 August 2024 (UTC)

I do not understand the technical things in Wikipedia. But are there other ways to change black to white lines during the use of dark-mode gadgets? Relatedly, I mean, the gadget is beneficial in reducing the amount of light that comes into one's eyes when reading an article. But for some reason, this gadget is already problematic, including PNG vector images, where the background of an image occasionally shows fully dark color with some distorted uncomfortable white dots near the black lines (see image on Square pyramid, or the GIF in Pentagonal pyramid#In polyhedron). I think this is already explained in an essay or whatever it is. Dedhert.Jr (talk) 02:46, 8 August 2024 (UTC)

Big traffic spike to Triangle

Apparently there were some kind of puzzles or codes in the recently released Book of Bill (related to the childrens' TV cartoon Gravity Falls) whose answers included "Triangle" and "Eye of Providence", with the result that those pages have seen massive view spikes. Triangle went from a norm of about 800–900 views per day up to 500,000 views yesterday, and possibly more today.

If anyone wants to have improvements to a mathematical page widely seen, Triangle could use some love.

(I added {{talk page header}} to Talk:Triangle hoping it would forestall some of the graffiti being directed there. Are there other good ways to deal with giant traffic spikes like this?) –jacobolus (t) 22:49, 11 August 2024 (UTC)

@Jacobolus Triangle was used to be FA. If anyone wants to improve, especially to revive it, I think I can help, but I need a lot of work. Some advices or comments may be required. Whether the goal is to become GA or FA, that implies the article is suitably referenced and on-topic. Dedhert.Jr (talk) 00:58, 12 August 2024 (UTC)

To be honest I don't care much about GA or FA, but it would be nice if the article were better sourced and more complete. –jacobolus (t) 01:01, 12 August 2024 (UTC)

Okay. I have made it on my sandbox, and the progress is on the way. For someone who would like to give comments or advice for improvement only, ask me on my talk page. Dedhert.Jr (talk) 03:56, 12 August 2024 (UTC)

I have some problems while expanding the article. In the case of non-planar triangles, I found out that there are other triangles as in hyperbolic triangle and spherical triangle. However, I also found out that hyperbolic triangles can be constructed by a so-called Thurston triangle [1]. It also contains the area of a hyperbolic triangle by using Gauss–Bonnet theorem, but according to which it is a geodesic triangle. Dedhert.Jr (talk) 11:38, 14 August 2024 (UTC)

It's unfortunate that we don't yet have an article spherical triangle, and that spherical trigonometry and spherical geometry are so incomplete. These and the many related topics which are currently red links or redirects are on my long-term todo list, but fixing even a few of them properly is a large daunting job and it's hard to get started. I'd eventually like to make a substantial number of diagrams similar to those at Lexell's theorem, but each one takes at least an hour of fiddling, sometimes several. Anyhow, both spherical triangles and hyperbolic triangles are types of geodesic triangles, with edges that are geodesics of their respective spaces.

What your linked article calls the "Thurston model" of hyperbolic space is a discrete (infinite) polyhedron analogous to the regular icosahedron as a model of a sphere. The vertices are those of the order-7 triangular tiling; if you wanted you could put them all on one branch of a 2-sheet hyperboloid in 3-dimensional Minkowski space of signature (2, 1), and then the flat faces would be space-like triangles in the ambient Minkowski space. You could project from the hyperbolic plane onto those triangles, e.g. using the Gnomonic projection, or you can draw shapes directly in the space of the polyhedron. You could do something similar with any other kind of polyhedron. I don't think the article triangle needs to spend much if any time discussing triangles drawn the surfaces of polyhedra. –jacobolus (t) 18:07, 14 August 2024 (UTC)

Another problem: Do you think the conditions about the importance of similarity and congruence sections should be trimmed away? Not something beneficially useful including the article on triangles in general; HL and HA theorem may be included in Right triangle instead. The same reason for the similarity of triangles via trigonometric functions. However, one exception that I include is its relation with trigonometric function, defining their functions as a ratio between both sides in a right triangle, and then including the law of sines and cosines as well. Dedhert.Jr (talk) 05:43, 15 August 2024 (UTC)

Another problem: The article Triangulation (geometry) is somewhat short and unsourced in some areas. Do you think this article should be expanded, or rather redirected to the section of the article Triangle? Dedhert.Jr (talk) 05:43, 15 August 2024 (UTC)

Triangulation (geometry) should definitely be its own article, and does not make sense to redirect. But feel free to dramatically expand it. It's a large topic about which whole books have been written. –jacobolus (t) 16:03, 15 August 2024 (UTC)

Ahh, I think something is missing here. Can somebody remind me, or give me more ideas to expand more in my sandbox? I could think of removing "triangles in construction" as in the Flatiron Building and truss; most of these topics are supposed to be triangular prism and isosceles triangle, respectively. The same reason for calculating the median, circumscribed and inscribed triangles, and many more, since they do have their own articles. Dedhert.Jr (talk) 05:43, 15 August 2024 (UTC)

"Triangles in construction" isn't the best section title or scope, but there should definitely be at least a section about how triangles are the only polygon which is rigid when the side lengths are fixed but the sides can rotate independently about the vertices; this is why triangles are the fundamental shape used in a truss, explains why a 4-bar linkage is the most basic type (a "3-bar linkage" can't move), is a reason triangulation works in surveying, and so on.

There should probably separately be a discussion of the use of triangles as common decorative elements etc. –jacobolus (t) 16:02, 15 August 2024 (UTC)

Triangles are definitely not the unique basis for rigid linkages; see Laman graph. The utility graph $K_{3,3}$ is I think the simplest triangle-free rigid graph (in 2d). —David Eppstein (talk) 18:04, 15 August 2024 (UTC)

That's an interesting subject well worth discussing in Laman graph or structural rigidity, but the utilities graph isn't a polygon, and isn't really relevant to the point that the triangle's rigidity is the reason for many of its practical applications. Edit: Maybe Triangle § Rigidity would be a good top-level heading for Triangle. –jacobolus (t) 19:56, 15 August 2024 (UTC)

@Jacobolus. Okay. I would probably do more research and apply them to my sandbox. One problem here is I still cannot find the sources about the rigidity of a triangle and its tessellation with a hexagon. Dedhert.Jr (talk) 05:55, 16 August 2024 (UTC)

Completion

@jacobolus. The article is done for refactoring and rewriting. But some sources may needed to complete the article. Do you have any comments about something is missing or superfluous in the article? Let me know. Dedhert.Jr (talk) 07:48, 17 August 2024 (UTC)

Thanks for putting in the time and energy. XOR'easter (talk) 21:18, 19 August 2024 (UTC)

I've made a smattering of edits to fix small prose matters and fill in some citations. It's still a little under-referenced, so anyone else who'd like to jump in and work on that should feel more than welcome. XOR'easter (talk) 23:30, 19 August 2024 (UTC)

I appreciate your work, as well as the compliments. Still have problems, however, especially with the sources of Heath's book The Thirteen Books. The first book's Definition 20 describes the isosceles triangle definition according to Euclid, but I think this is a mismatch with the given page in Isosceles triangle, or it is hidden in the Greek writings. Pinging @David Eppstein for further explanation. There is a similar reason for Heath's footnotes being more numerous. Dedhert.Jr (talk) 02:51, 20 August 2024 (UTC)

Maybe I'm misreading your comment: do you mean there is a mismatch in Euclid's definition, or just with the formatting of the reference? If the former, you should read the Usiskin & Griffin source from both articles. There are two different and incompatible ways of classifying shapes:

• In exclusive classification, all cases must be disjoint: each shape can have only one type
• In inclusive classification, special cases are subsets of more general cases

As our isosceles triangle article states, Euclid uses an exclusive classification, in which isosceles triangles must have exactly two equal sides and in which equilateral triangles are not isosceles. Many other sources use an inclusive classification in which equilateral triangles are special cases of isosceles triangles. But both remain in use.

Using an inclusive classification and allowing classes to be subsets of each other can be more flexible and avoids unnecessary case analysis. For instance, when Euclid proves a theorem about isosceles triangles, he would have to prove the same theorem again for equilateral triangles, because the givens from the first theorem would not match the definition needed for the second theorem. And when does a special case become separate from the general case? Maybe isosceles right triangles aren't isosceles triangles, because they are in a different special case class?

The same issue comes up even more strongly for quadrilaterals, where one may reasonably ask whether parallelograms are trapezoids, whether rectangles or rhombi are parallelograms, and whether squares are rectangles or rhombi. And then one must reconcile this classification with cyclic quadrilaterals, tangential quadrilaterals, orthodiagonal quadrilaterals, kites, bicyclic quadrilaterals, etc. In the isosceles triangle case, either definition was easy enough to write, but for many of these other cases of quadrilaterals, the inclusive definitions are easy to write (it's a quadrilateral for which a specific constraint is true) and the exclusive definitions are much messier (the constraint is true but also some other constraints that would cause it to be a more specific special case are all false).

Most of the time we use inclusive classification in our Wikipedia articles, but this distinction should be explained. And it's important that this choice be made in a principled way rather than randomly and inconsistently from one article to another because of the sources you happened to read when you were working on the article.

If I'm misinterpreting and this was all purely about page numbers then sorry for the off-topic rant. The important part of the Euclid reference is "Book 1, definition 20". —David Eppstein (talk) 04:25, 20 August 2024 (UTC)

@David Eppstein What I meant is in the article Isosceles triangle, you cited Euclid's definition on page 187 [Heath (1956), p. 187, Definition 20.] But I cannot find that definition on that page. What I meant about Greek letters is, even though I found the "Definition 20" on a different page, I will never find that the definition, and it is possibly written in Greek language. This is why I leave this to you since you are the nominator of that GA. and I have no clue about the article's expansion back of the day. Anyway, thank you for your explanation above. Dedhert.Jr (talk) 05:12, 20 August 2024 (UTC)

I can check my copy the next time I'm in the office. Are you sure you're looking at Vol.1 of the Dover three-volume edition? There are a lot of different reprints of Heath's translation. If you're reading it in Greek then I think you have a different one; I would have referred to an English translation. —David Eppstein (talk) 05:33, 20 August 2024 (UTC)

@David Eppstein I have searched it on Heath's citation, which I pointed out in the recent replies. As far as I'm concerned, the page describes the Greek language as the definition and English is probably the further explanation and comments. Look at the page 292 that I linked here [2]. Dedhert.Jr (talk) 05:45, 20 August 2024 (UTC)

"Heath's citation" is ambiguous. There are many reprints of Heath's translation of Euclid. Again, are you sure you're looking at Vol.1 of the Dover three-volume edition? The link you give is to Book 7 in Vol.2, not to Book 1 in Vol.1. —David Eppstein (talk) 06:09, 20 August 2024 (UTC)

@David Eppstein Sorry but that source is already linked as a reference or works cited in the Isosceles triangle, see the references:

• Heath, Thomas L. (1956) [1925]. The Thirteen Books of Euclid's Elements. Vol. 1 (2nd ed.). New York: Dover Publications. ISBN 0-486-60088-2.

Dedhert.Jr (talk) 10:16, 20 August 2024 (UTC)

Apparently the incorrect link is the fault of User:InternetArchiveBot: [3]. Reported: T372925. —David Eppstein (talk) 17:25, 20 August 2024 (UTC)

Ideally we should be citing the Cambridge University Press 2nd edition from 1926, which was later reprinted by Dover, and including a link to a scan of the appropriate page with every reference. Unfortunately the internet archive only has a scan of volume 3, and many of their scans of dover reprints are blocked or need to be "checked out" (though they shouldn't be, since the copyright is still 1926, and expired). HathiTrust has a scan of vol 2 (and vol. 3). –jacobolus (t) 15:49, 20 August 2024 (UTC)

What we need in this case is vol.1. —David Eppstein (talk) 17:31, 20 August 2024 (UTC)

Is this it? Of trilateral figures, an equilateral triangle is that which has its three sides equal, an isosceles triangle that which has two of its sides alone equal, and a scalene triangle that which has its three sides unequal. XOR'easter (talk) 17:49, 20 August 2024 (UTC)

Yes. And the page number matches, answering Dedhert.Jr's question. —David Eppstein (talk) 18:00, 20 August 2024 (UTC)

Template:Equation in andriod dark mode

A couple of users complain that equations in boxes are not viewable on Android in dark mode. The highlighting of the box is a nice-to-have. Is there any workaround short of removing the template? Johnjbarton (talk) 14:55, 14 August 2024 (UTC)

Oh, turns out the template is "Equation box 1" (ugh) and there are some hints about dark mode issues. Johnjbarton (talk) 15:20, 14 August 2024 (UTC)

I partly fixed this issue, but it turns out this template is mainly used in physics articles. Johnjbarton (talk) 18:10, 15 August 2024 (UTC)

Another problem is {{Dynkin}}. Tito Omburo (talk) 16:40, 20 August 2024 (UTC)

Does this project cover numeral systems?

I was having a similar discussion on Wikipedia talk:WikiProject Numbers, but they didn’t have a clear answer yet –it would be great if someone could make it’s more clear. Legendarycool (talk) 22:41, 19 August 2024 (UTC)

If you run into conflict or some other difficulty in articles about numeral systems, you can certainly bring discussion here for more eyes. Is there something specific you are interested in / working on? –jacobolus (t) 00:54, 20 August 2024 (UTC)

No nothing at the moment, just for future reference. Legendarycool (talk) 02:02, 20 August 2024 (UTC)

TFL List of Johnson solids

Participants of this member are allowed to give opinions on whether the article List of Johnson solids is submitted on a given date. Dedhert.Jr (talk) 05:05, 20 August 2024 (UTC)

Skolem's Paradox

Hello WikiProject Mathematics. Recently I noticed that the article Skolem's paradox had very few inline citations, so I decided to fix the refs and tweak some things. Now I've been working on it enough that I'd like to take it to GA review, but I would really appreciate if anyone could read through it first, especially someone with the knowledge to verify the "The result and its implications" section. I think that the first "formal" explanation of the paradox in that section is a bit weak. Thanks, Pagliaccious (talk) 01:20, 21 August 2024 (UTC)

Requested move at Talk:Hilbert system#Requested move 20 August 2024

There is a requested move discussion at Talk:Hilbert system#Requested move 20 August 2024 that may be of interest to members of this WikiProject. Rotideypoc41352 (talk · contribs) 21:54, 21 August 2024 (UTC)

Uncited and vague statement at Trigonometric functions

This line in Trigonometric functions is tagged for temporal vagueness and needing a reference: The modern trend in mathematics is to build geometry from calculus rather than the converse. Is this remark actually true, and if so, is it worth saying in that spot? It seems to me that talking of a singular "trend" in mathematics is likely to be unsupportable. If one is doing coordinate geometry, one might found it upon properties of the real numbers as developed in real analysis, which is the sophisticated version of/groundwork for/elective taken after calculus. But to a reader for whom geometry is a prereq to calculus, this statement is probably rather puzzling. XOR'easter (talk) 23:21, 21 August 2024 (UTC)

This seems more or less right, but may be unnecessary here, and could be significantly elaborated. Our description both here and at trigonometry and history of trigonometry is extremely incomplete. As for when this occurred, as concerns trigonometry per se this approach more or less originates with Euler, but picked up steam with Fourier series and then efforts to make them more rigorous in the 19th century, and by studies of elliptic functions, &c. With respect to geometry more generally, I'd also say this is a trend, with pure mathematicians treating geometry as founded in analysis (and its offshoots of topology and set theory), more and more over time starting in the 18th century but since the 20th century almost completely. You could extend this general trend earlier if comparing the gradual substitution of coordinates and analytic geometry in preference to Greek definitions and "synthetic" methods. –jacobolus (t) 00:11, 22 August 2024 (UTC)

I've given it a go, but I think the article needs some organizing. Also, there is no mention of asymptotes. Tito Omburo (talk) 01:14, 22 August 2024 (UTC)

I'm not sure the gesture toward G. H. Hardy is any more helpful to readers than the previous vague handwave about trends away from geometry. I'd just cut those prefatory sentences and discuss the broader context more thoroughly in the history section and in history of trigonometry.

This and related articles could definitely use organizing. There could also be separate articles about tangent (trigonometry) and secant (trigonometry) to go along with sine and cosine, which would leave more room for discussing more specific history, applications, etc. –jacobolus (t) 05:06, 22 August 2024 (UTC)

A problem with the previous vagueness is that it was an unreferenced point of view. Also, the assertion that there are "two ways" to define the trigonometric functions was flat out wrong. Hardy lists four, not including the first one described in the article (which I found in Bartle and Sherbert). Tito Omburo (talk) 09:58, 22 August 2024 (UTC)

A minor point: I don't understand why there's so much name-dropping/attribution in your addition. One can write "there is a problem with geometry as a definition.[ref: hardy] there are mutliple modern approaches to fix this: (1)(2)(3)(4).[refs:hardy, bartle-sherbert]" What is added by announcing at the beginning of these sentences that the references at the end of the sentence are written by Hardy and by Bartle--Sherbert? --JBL (talk) 17:54, 22 August 2024 (UTC)

I'm not married to the wording, but it seems like this is the basic content and sources that should be there. Tito Omburo (talk) 20:31, 22 August 2024 (UTC)

"Build geometry from calculus"? What is being referred to here? Michael Hardy (talk) 02:35, 22 August 2024 (UTC)

I'd say that The modern trend in mathematics is to build Euclidean geometry from calculus rather than the converse. is generally true, but that the more general statement is false. I'm having trouble coming up with a replacement that is both accurate and concise enough to be in the lead. -- Shmuel (Seymour J.) Metz Username:Chatul (talk) 13:12, 22 August 2024 (UTC)

This statement is basically true from the perspective of a differential geometer, but not from the perspective of an algebraic geometer. I think this statement should be expanded upon or removed because it is just way too vague to be helpful. In the context of trig, it might be more helpful to say that nowadays people define trig functions using calculus and then define angles using trig functions. Mathwriter2718 (talk) 13:39, 22 August 2024 (UTC)