Please help by writing tag wikis for your favorite tags!
Use answers to this post to suggest tag synonyms.
Finally, if you're a 10k+ user, note how easy it is for you to edit tags now!
Here’s a few words of advice on writing tag wiki excerpts:
The excerpt is the elevator pitch for the tag. You only have ~500 plain text characters for the excerpt, so don’t feel obligated to cover everything in it! Save that for the 30,000+ character Markdown tag wiki. The excerpt should define the shared quality of questions containing this tag — boiled down to a few short sentences.
Avoid generically defining the concept behind a tag, unless it is highly specialized. The “email” tag, for example, does not need to explain what email is. I think we can safely assume most internet users know what email is; there’s no value in a boilerplate explanation of email to anyone.
Concentrate on what a tag means to your community. For “email” on Server Fault, mention the server aspects of email including POP3, SMTP, IMAP, and server software. For “email” on Super User, mention desktop email clients and explicitly exclude webmail, as that would be more appropriate for webapps.stackexchange.com.
Provide basic guidance on when to use the tag. In other words, what kinds of questions should have this tag? Tags only exist as ways of organizing questions, so if we don’t provide proper guidance on which questions need this tag, they won’t get tagged at all, rendering the tag excerpt moot. Think of it as a sales pitch: in a room full of tags screaming “pick me!”, what would convince a question asker to select your tag?
Some tags are common knowledge. Most tags require a bit of explanation in the excerpt, even if it’s only 3 or 4 words. But if the tag is common knowledge — that is, if you walked up to any random person on the street and said the tag word to them, and they would know what you were talking about — then don’t bother explaining the tag at all. Stick to usage of the tag within your community in the excerpt.
I think it is not necessary to have separate tags here and one ICMs tag should suffice.
Actually, I do not even think this ICM tag is necessary, conferences should suffice.
The numbers of questions involved here are small, but I rather would like to avoid reactivating the old icm-2010 questions, thus this request for merging or synonyming. (Also I do not want to retag icm-2014 manually if ever there is then opposition to the merge.)
There are tags lattices and lattice-theory, both being used for the two unrelated meanings “partial order with binary suprema and infima” and “discrete subgroup of $\mathbb R^n$”. I’m not sure it’s feasible to sort out the ~300 questions involved, but maybe we could try at least to alleviate the problem for future by deciding which tag is supposed to denote which meaning, renaming them unambiguously, and supplying tag summaries. If not, the tags should be merged.
I have noticed that the tag duality is quite often used for questions about dual spaces in functional analysis and linear algebra. However, it's not immediately clear from the tag name that this is intended. (Although the current revision of the tag-excerpt explicitly mentions dual spaces.)
In addition to that, duality is a word which is used in several different - although related - meanings.
Perhaps it is worth mentioning in connection with this that there already exists tag called dual-pairs which might be used in context of functional analysis. (But from the usage it seems that it is used in other meanings, too. The tag-info is empty at the moment.)
Resolved: There is no longer kahler tag and we have kahler-manifolds tag. The new name for differential-graded-lie-a is now differential-graded-lie-algebras. (After the limit for tag names was increased to 35 characters.)
Tag 'kahler': I was wondering if the tag 'kahler' should be renamed 'kahler-manifolds' (or something like it), so as to make it more descriptive and less prone to confusion. I have browsed through all the questions with the tag 'kahler' and all of them are indeed about Kähler manifolds. This means the renaming would be an easy process, but it may also mean that it is not necessary. Any opinions?
Update: The tag 'kahler' no longer exists and 'kahler-manifolds' now exists in its place.
Tag 'differential-graded-lie-a': Here is another suggestion that may or may not be desired. Due to the character limit for tags, some long tags may become hard to understand. The worst offender I have found so far is 'differential-graded-lie-a' (with only two questions). This could very well be made a synonym of 'dg-lie-algebras' if people think there is a benefit.
For questions related to divisors in the sense of algebraic geometry (Cartier divisors, Weil divisors and so on). For question on divisors in the number theoretic sense please use the tag divisors-multiples.
Still, some people might not notice the tag-excerpt, and if they look only at the name of the tag they might assume that the words is used in number-theoretic meaning. (For example, the questions which are currently tagged divisors+nt.number-theory are most likely mistagged. And there are a few more examples of questions which originally had (divisors) tag and it was later corrected to (divisors-multiples) tag.)
I am not really sure what would be a good name for the tag. So I'd be grateful if you have some reasonable suggestions in comments.
I would probably suggests simply divisors-algebraic-geometry following the title used in Wikipedia article Divisor (algebraic geometry). I have seen that Ricardo Andrade suggested scheme-divisors in chat. Joe Berner mentioned the (already existing) tag algebraic-cycles, but immediately added also that algebraic cycles and divisors are not the same thing, so these two tags should stay separate. See also his comment below this post.
A few years ago a separate question about divisors tag was posted: What subject specific tags could replace the tag 'divisors'? However, it did not generate much discussion (only two comments).
I'd like to propose creation of continuum-theory tag.
To me (as an outsider, but still a bit interested in this topic) it seems that continuum theory is an area of general topology which enjoys some interest both among topologists and among mathematicians in general. (For example, one part of Open Problems in Topology is dedicated to continuum theory - 2 chapters in the first volume, 8 chapters in the second one.)
Quick search reveals several questions on the main with the word continuum or continua - of course, sometimes this word might be used in different meanings, but if you browse a bit among the search results you can see that several of those question are from this area or closely related to this topic.
Resolved: The tag synonym has been created.
Based on the reception of the question Pronunciation questions (currently at score 22) it seems that questions about pronunciation are on-topic on this site (within some reasonable limits).
I suggest creating pronunciation tag for questions asking about pronunciation of mathematical terms, mathematical symbols and notation, names of mathematicians, etc. If we have a tag for such questions, this would make easier for the poster of a new question to check whether his question has been asked before.
I will add that (pronunciation) tag exists on Mathematics site.
Currently (Dec 6, 2021)
I think there is no sensible difference justifying the distinction between these two tags. As regards which one should be made synonym: while the first might look slightly more specific, the fact that it has more occurrences simply reflects that people asking questions in this area rather have in mind the keywords "machine learning". I tend to prefer the second one (i.e., making the first one synonym of the second one, rather than vice versa) because learning-theory is slightly more generic, and makes it clearer that this is a mathematical subject.
We have convexity tag - it has empty tag wiki, but I understand the tag broadly as stuff related to convexity, convex functions, convex sets, etc. (Of course, for some of such questions convex-analysis or convex-geometry are more suitable.)
For some time there was concavity tag, see here. The tag was later deleted by an automated process which removed the tags which removes the tags used on single questions after certain time (unless the tag has a tag-wiki). As a result, the question where the tag was created is currently tagged untagged - since it was the only tag there.
If somebody is willing to write tag-info for convexity, perhaps concavity could be mentioned there, too. (Since the questions in this tag are a bit diverse and I am not really sure what were the original intentions when the tag was created, I don't think I would be able to create a good tag-wiki with clear explanation when this tag is supposed to be used. So I will leave this to more experienced users.)
Mathematical questions related to mathematical software systems such as Sage, Mathematica, Maple, Pari/GP, and GAP. Note that troubleshooting questions are generally considered off-topic.
I think that one tag for both topics might be enough. It seems that at least some of questions in (software) tag are actually about (mathematical-software). (Probably depending on your definition what you consider mathematical software.) In both these tags we have some questions about various drawing tools - perhaps these can be considered mathematical software. Other than that, the only questions which are currently tagged software and where (mathematical-software) would be clearly bad fit are Tools for Organizing Papers? and What programming languages do mathematicians use?. (The latter is closed.)
I would suggest creating a synonym mathematical-sofware $\to$ software. (Choosing latter as a master tag simply because the name is more general, majority of the question is very likely be about mathematical software.)
If there are reasons to keep them separate, editing the tag-info for both tags to make the distinction clearer would be useful.
I think that it is quite probable that users asking about question which are on topic might look for a tag with a similar name. Several metas in SE network have a tag called (on-topic).
What about creating small-uncountable-cardinals tag? (The tag name is within the recently increased 35 character limit.)
Looking at the main site, it seems that small uncountable cardinals (such as $\mathfrak p$, $\mathfrak t$, $\mathfrak b$, $\mathfrak d$, etc.) get quite a lot of attention on this site. For example, if you search for either of the cardinals mentioned before in the set theory tag, you can find a bunch of questions: p, t, b, d.)
I think that creating a separate tag for this topic might made searching for such questions easier. Additionally people who are interested in the topic could follow the tag. (I.e., they could get those questions highlighted, they have easier access to recent questions in their favorite tags, etc.)
Of course, it is possible to consider also other candidates for the name of the tag. Wikipedia uses Cardinal characteristic of the continuum. (For example, cardinal-characteristic-continuum is under the 35 characters limit.)
If the consensus is that the tag small-uncountable-cardinals would be too specific and it is better not to create such tag, I would be grateful also for comments suggesting which tags can be used for questions where small uncountable cardinals are the main topic. In the past I have sometimes added infinite-combinatorics to such questions - was it a reasonable choice?
The tag analysis-and-odes has only five questions and empty tag info - so it does not seem to have any distinction from ca.classical-analysis-and-odes. Four of the five questions in this tag were asked by the same user, but since thy no longer have account on MathOverflow, we cannot even ask them whether their intention was to create something different from the existing top-level tag. For the list of questions, see here and here.
A reasonable alternative would probably be also to remove the tag manually, but a synonym solves the problem without bumping old question. And another advantage is that if somebody tries to create this tag in the future, it will automatically be changed to the ca.classical-analysis-and-odes tag.
The tag etcs has now 7 occurrences [edit: had 7 occurrences].
It stands for "elementary theory of the category of sets". I suggest to manually change it to elementary-theory-category-sets. (This is 31 letters. elementary-theory-category-of-sets would be 34 letters, is maybe suitable too.)
I believe abbreviations should be avoided in tags (exceptions only being very famous ones such as PDE, ODE).
Edit: now changed to elementary-theory-category-of-sets.
I see no difference at all between the two. Each has its tag info.
matrices (now 2900 questions): Questions where the notion matrix has an important or crucial role (for the latter, note the tag matrix-theory for potential use). Matrices appear in various parts of mathematics, and this tag is typically combined with other tags to make the general subject clear, such as an appropriate top-level tag ra.rings-and-algebras, co.combinatorics, etc. and other tags that might be applicable. There are also several more specialized tags concerning matrices.
matrix-theory (now 420 questions) Matrix theory is the study of matrices as concrete objects, rather than as abstract linear operators between vector spaces (whose study belongs to linear algebra). For instance, this involves matrix factorizations and decompositions, nonnegative matrices and Perron-Frobenius theory, Schur complements, structured and special matrices, matrix functions and equations.
(There are indeed more specialized tags on matrices, but I don't think matrix-theory applies.)
There was tag open-problems-list for questions asking list of open problems in certain area or more generally satisfying certain criteria.
But it disappeared recently. I do not think it is good. Can we revert it?
There is tag "open-problems" but that tag is very general and there too many questions on specific open problems, so it is not convenient to find "open problem LISTs" questions.
There is a tag closed-questions on meta. If you look at the questions, some of them are not about questions which are already closed, but more about process of closing. (E.g., how is question closed, when it can/cannot be closed, etc.)
I would suggest to:
If there is some agreement that we should have both questions about closed questions and the process of closing questions under the same tag, this should be also added to the tag-excerpt/tag-wiki. And I think that on-hold questions could be included under the same tag.
I will add a comparison with other meta site - the one which I am most familiar with. On Mathematics Meta there are three separate tags closing, closed-questions and on-hold-questions. This sometimes makes users unsure which of the three tags to use.
I have noticed that there is a tag called interesting-tags on meta. It is actually one of the default tags - these are the tags that are automatically created on every new meta site and are not deleted even if they have zero questions.
You may notice that on Meta Stack Exchange, this tag is now a synonym of (favorite-tags). And I'd guess most users know this feature under the name favorite tags. (Maybe it was called differently at the time when the default tags were selected.) I think that average user would have hard time guessing what (interesting-tags) is intended for. Which might lead to inconsistent usage of this tag and some incorrectly tagged questions. (As you can see in this chat transcript the tag has been used on some question on meta - here and here - and in neither of the two cases in the intended meaning. To be honest, I was quite puzzled when I saw the tag for the first time.)
My suggestion is to clarify usage of this tag and also make the name correspond to today's terminology.
If you look at current usage of the tag favorites and also if you check current revision of the tag-excerpt and the tag-wiki, you can see that this tag is currently used for both favorite tags and favorite question. (I am partly to blame - I have used the tag in this way and also I have created the tag-info. However, it seemed to me a bit redundant to create a separate tag for favorite tags.)
This means that if we decide to have a separate tag for favorite-tags, this would require also retagging of a few older questions. Which is why I am inclined more to the latter option, i.e., to have one tag for both favorite tags and favorite question.
But I am certainly open to the other solution. We can discuss (and vote) in comments which of the two options is better.
On meta there are two tags searching and search. The latter is one of the default tags - these are the tags that are automatically created on every new meta site - which essentially means that it cannot be removed.
I would suggest creating a synonym search $\to$ searching. Having two tags for the same topic could lead to confusion which tag to choose and also to inconsistent usage of tags - and, consequently, this would make searching using tags a bit difficult.