This question already has an answer here:

New year, new tag management thread.

Rules of the game are basically the same:

  • Post your suggestion as an answer here if you see
    • A particularly bad tag (a rule of thumb: «if I can't imagine a person classifying a tag as either interesting or ignored, I'm getting rid of it»),
    • A tag that should be a synonym of an existing one,
    • A tag that used for two or more completely unrelated things,
    • A need to create a new tag;
  • Upvote/downvote/comment as your agree/disagree with suggestions, so please post different suggestions in separate answers;
  • Wait a couple of days before implementing a suggestion.
  • After the problem described in an answer is resolved, please edit it to say so.
  • If your tag suggestion exists in a separate question, please provide a link to the question in your suggestion.

See also:

Also, note that one may use [tag:calculus] for , i.e. tags on the main site, and [meta-tag:discussion] for , i.e. for tags on the meta site.

marked as duplicate by Asaf Karagila discussion Jan 2 at 0:17

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • I recently proposed changes to tags concerning quaternion algebras here. I would appreciate more feedback in the form of votes on the three answers. – Quasicoherent Jan 17 '17 at 4:51

35 Answers 35

Resolved. All occurrences of the tag have been removed.

I suggest to remove tag.

This tag was created in December. The tag creator also provided the tag-excerpt and the tag-wiki which more-or-less follow the Wikipedia article Theory of equations. Looking at the tag-info, it seems that most of the problems described there are covered by .

In short, I do not really see which area not covered by the already existing tags should be used for.

  • The tag name itself is odd, being a term that fell out of use many decades ago (note that the Wiki article suggests as much). I concur with getting rid of it. – epimorphic Feb 19 '17 at 2:22

The list of proposals on the 2016 thread that are still open:

Feel free to comment below if anything should be added or removed.

  • Are "lattice-paths" and "polyomino" same? – Takahiro Waki May 9 '17 at 16:36
  • 2
    Finally, some progress on the requests from the last thread. It only took over 10 months to get one of them done. By this rate we'll finish the 2016 stuff around 2027. Hopefully nothing else will backlog, so we could finally have a relatively clean slate of tag requests by January 2028. – Asaf Karagila Nov 26 '17 at 20:23

Can we rename to or something?

Resolved: now exists and is a synonym.

EDIT: Since this post reached score +6 (which shows some support) I went ahead and created . I have also created a very basic tag-info.

I still think that synonym with might be useful. (But other names used for this type of integral are probably not widespread enough to be considered as suitable names for tags.)

I propose creating a tag . (Perhaps also with synonym .)

There are some questions on the main site about this type of integral. Perhaps not that many, but it seems that some users are interested in this topic.

However, searching for questions concerning gauge integral is not that simple, since it is known under various names: gauge integral, Henstock-Kurzweil integral, Kurzweil-Henstock integral, perhaps less frequently narrow Denjoy integral, Luzin integral, Perron integral, generalized Riemann integral. See also the Wikipedia article. Search on main sites returns:

Trying other names mentioned in the Wikipedia article only returns question on different topics, or questions which already contain some of the above keywords (narrow Denjoy, Perron, Luzin).

Resolved. has been renamed (merged into) , and the synonym has been created.

Proposal: Rename to "sagemath"

  • The tag is about the software sagemath, so why is it called sage?
  • People could get confused about what the sage tag is for. (When I first saw the tag I thought of something like this)

The current "sage" tag could be added to the new tag as a synonym, or vice versa. But I prefer "sagemath" being the main tag name.

  • 2
    I'm not really sure how I feel about this. The software is essentially known by both names, although as of 2015, it is apparently officially SageMath. I've always believed it's just known as SageMath occasionally to disambiguate from other uses of Sage outside of mathematics, like Simon & Garfunkel songs (indeed, see this help page: "the short name keeps being used when there is no ambiguity"). I don't really see any risk of ambiguity here, so I don't see any reason to change. But maybe I'm overly stubborn. – pjs36 Jan 17 '17 at 2:46
  • 1
    Could we make synonyms? Are there already synonyms? – Quasicoherent Jan 17 '17 at 4:53
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    But in the short span of a couple of hours, I'm less sure of my initial stance. William Stein has said that Sage is failing without enough people using or adopting it. If changing the name of the tag will help people realize that it's referring to (really good!) software, while being the program's latest official name, that may be reason enough for a change. – pjs36 Jan 17 '17 at 6:03

Resolved (for now): This post reached score +5 which shows at least some consensus on the issue, so I went ahead and removed all occurrences of the tag.

The tag has been created recently, most likely in this question: Resolution of a linear system and optimization problem.

Another user (not the tag creator) created a rather short tag-excerpt (saying just: "For questions about linear systems.") and a tag-wiki which says:

A linear system is a mathematical model of a system based on the use of a linear operator. For more information, see linear system.

So far there are two questions in which, as far as I can say, it is used for system of linear equations. The current revision of the tag-info seems to indicate a slightly different usage than in the questions tagged so far by this tag. (Or perhaps we could say more general.)

Moreover, the questions about systems of linear can already be tagged by and . This combination of tags has been used for such question in the past, you can see that there are currently 850 questions tagged linear-algebra+systems-of-equations. So if this new tag is supposed to be used for systems of linear equations, in those questions we should probably replace (systems-of-equations) by (linear-system).

When somebody looks only the tag name, other possibilities that come to mind are linear dynamical systems and systems of linear differential equation.

So the two questions are:

  • Should we keep the tag?
  • If yes, what type of questions should it be used for? (If some consensus is reached, this should be clarified.)
  • If we keep the tag, perhaps it should be pluralized to . (Most of the tags we have are in plural.)

My personal opinion is that the tag could be removed. (We already have tags covering this topic. Moreover, the new tag would require rather large retagging effort. In addition to that, the intended usage of the tag seems unclear.) But I would like to know about opinion of other users on this issue.

Of course, if a more extensive discussion about this is needed, we can create a separate question.

  • I agree with your proposal to replace (systems-of-equations) with (linear-system), which is the ambiguity that made me created this tag. – E. Joseph Feb 25 '17 at 13:13
  • 1
    @E.Joseph I edited the question to make clear that I consider completely removing the new (linear-system) tag as the best way to go. (Before the edit, I did not made any proposal in my post, I just tried to explain what would keeping this tag mean for already existing questions. I apologize that my post was not clear enough.) – Martin Sleziak Feb 25 '17 at 13:20
  • @E.Joseph I assume you know this, but just in case: Since you state in your comment that you disagree with the removal of the tag, I'll just mention that since the post has been edited, you can change your vote. (That is, if you voted on the post before the edit.) – Martin Sleziak Mar 7 '17 at 14:06
  • Thank you for your consideration, but since it's fine either ways (both ways have advantages), I decided to keep my +1. – E. Joseph Mar 7 '17 at 14:08

Resolved. Tags merged and synonym $\to$ created.

Proposal: Rename to "spin-geometry".

Most of the questions with the spinor tag are really about spin geometry; spinors are just a particular aspect of spin geometry. It currently isn't clear if one should use the tag if the question is about other questions related to spin/spin$^c$/pin$^{\pm}$ structures and their associated geometry.

  • 2
    Perhaps leaving also spinor but making it synonym of master tag spin-geometry might be useful. (So that if some people search for spinor tag, spin-geometry is added automatically.) – Martin Sleziak Jan 30 '17 at 13:19
  • 1
    I think it would be best if somebody knowledgeable in the field (the prime candidate would be you, @Michael) creates the tag spin-geometry with a tag wiki first, and then we do the synonym + merge dance. – Daniel Fischer May 13 '17 at 10:55

I think it's silly to have both and . We don't have a tag. We aren't going to add and (hopefully).

I don't really care how we merge the two but for the sake of having a proposal, let us create a synonym <- since has more questions attached to it.

For comparison, Wikipedia redirects positive semidefinite matrix to positive definite matrix.

  • 1
    The possibility of a synonym was also briefly mentioned in the comments here. – Martin Sleziak Jun 29 '17 at 17:01
  • Perhaps you could clarify in your post what action exactly are you suggesting. (From the wording of your post, it seems that you want to create a synonym (positive-semidefinite) $\to$ (positive-definite). But it would probably be better to say this explicitly in the post rather than let the readers guess.) – Martin Sleziak Jun 30 '17 at 6:22

There are 384 questions tagged . This appears to be a meta tag that I cannot really imagine anyone watching or searching for. I think it should be deleted.

  • Well potential test takers can definitely be interested... – Gabriel Romon May 8 at 14:01
  • Also, aren't the GRE questions confidential? – barto May 27 at 19:21

Resolved: The two tags are now synonyms.

Please merge and . I am active in these tags and the respective field and I fail to see a meaningful difference between them, let alone a need for a distinction.

This already got 10 upvotes last year.

Pre-resolved: The tag has been removed from the only question it was attached to, and should be deleted from the system soon. No need to create a mis-spelled synonym.

Proposal: Make a synonym of

Obviously, it's a misspelled tag that houses only one unanswered question, so I can't make this proposal on Math.SE's tag synonym page.

EDIT: Now there is question discussing tags for specific inequalities in general: Which (if any) inequalities with real numbers should have separate tags?

The tag has been created recently Is this really going to be useful? It seems a bit too specific to me.

In any case, it is probably worth discussing this on meta before the tag grows too large. (I'd guess that there is a lot of posts on this site where this tag might be relevant.)

I am not denying that the inequality is useful and well-known. However, it seems that we do not have usually tags for specific inequalities. There was a short-lived cauchy-schwarz tag. There were also tags chebyshev-inequality and gronwall-inequality for some short period. But these two inequalities are of different nature - they are from probability theory and from differential equation. Both Cauchy-Schwarz and AM-GM inequality are inequalities of real numbers.

Another problem with this tag is that sometimes it will be unclear whether the tag should be used or not. There are some clear-cut cases - for example, questions asking for proofs of AM-GM inequality or some things which are special cases of this inequality or immediate consequence. But it is not clear whether if a solution uses AM-GM, it is enough for the tag to be included. For example, of the two questions currently having this tag, in Prove that $x+\frac{1}{x}\geq2$ the tag clearly belongs there. However, it is less clear whether this tag should be used for $a,b,c,d>0$ and $abcd=1$ prove $\sum \frac {1}{(1+a)(1+a^2)} \ge 1$ since in this case AM-GM inequality is only one step in the solution proposed by the OP.

Of course, if there is need for a wider discussion which inequalities are important enough to have separate tag, a separate question on meta about this might be created.

  • Of course, since it is an important inequality, I am open to arguments explaining why we should keep the tag. So feel free to comment and make the case for this tag or at least downvote my post if you think the tag should stay. (So that we get some feedback from various users.) – Martin Sleziak Feb 3 '17 at 7:08
  • 1
    I'm torn about it. Initially I wasn't very fond of the tag, but the AM-GM inequality is something that's mentioned pretty often (and I wouldn't be surprised to learn that contest people use the site differently than I do, browsing questions for practice or something). However, I do wonder if the name was chosen poorly: I have seen several questions that could use the tag but don't, since its creation, and I wonder if the periods in its name make it less visible to those adding tags to questions. I don't have a strong opinion, but I think it's one of the better questionable tags. – pjs36 Feb 17 '17 at 12:48
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    I'm against it. Although the AM-GM inequality is important, it's very easy to use and I think it's unlikely that there will be a lot of questions along the lines of "help me use the AM-GM inequality." Usually when it's brought up (from what I've seen) it is brought up in an answer, and in a sufficiently simple way that if the OP knew to use the AM-GM inequality, then they wouldn't have needed help. – Stella Biderman Apr 5 '17 at 14:48

Resolved. All instances of this tag have been manually removed. (Thanks go to Jyrki Lahtonen.)

I suggest removal of tag. In fact, it seems that this was already suggested in the tag-excerpt and the tag-wiki - probably the user who made the edit did not know that such suggestions can (or even should) be posted on meta.1

It seems that the tag has been created for questions related to maximum modulus principle from complex analysis. But already since its inception the tag attracted mostly questions related to modular arithmetics.

I think that a tag with this name is very likely to lead to confusion and incorrect tagging even if the tag wiki explicitly specifies where it should be used. If a tag for maximum modulus principle is needed, then a tag with more descriptive name should be created. (Something like maximum-modulus-principle or maximum-modulus-theorem.)

1The tag-wiki currently reads: "This tag (modulus-theorem) attracts wrong questions. It should be closed and absorbed in the tag (modular-arithmetic). It is so rare that it is difficult to score the 5 points necessary to make a direct suggestion." The tag-excerpts says simply: "This tag is a poor synonym for (modular-arithmetic)."

  • I agree. I am currently manually removing the tag. Apologies for the bumping. – Jyrki Lahtonen Aug 6 '17 at 13:10
  • 1
    Done. If there is something I can do to prevent this from recurring let me know. – Jyrki Lahtonen Aug 6 '17 at 13:24

Right now there is:

This is clearly inconsistent. I think the ideal replacement would be

This got brought up before in 2015.

Resolved: The synonym suggestion had been removed.

I have noticed in the list of tag synonyms that recently the synonym $\to$ has been suggested. (It is possible to vote on this synonym here.)

First of all, since this synonym affects large number of questions, I do not think it should be created without being discussed on meta first. (The tag combinations contains over 3k questions. Tag-wiki is empty, tag-excerpt evolved like this.)

Personally, it think that combinations are legitimate separate topic in problems in combinatorics, so I would prefer the two tags to stay separate. (So consider +1 on this post as a vote in favor of keeping them separate and -1 as a vote in favor of synonymizing the two tags.)

  • Completely agree. This goes beyond my usual pet peeve of "not all combinatorics is enumerative" to "not all enumerative combinatorics is about combinations." – Trevor Gunn Aug 10 '17 at 13:43
  • I have notified the user who suggested the synonym. – Martin Sleziak Aug 11 '17 at 6:51
  • Did the synonym get voted away? – barto May 27 at 19:15
  • @barto It seem quite likely, since I do not see it anywhere. Thanks for letting me now! – Martin Sleziak May 27 at 19:17

EDIT: I have posted a separate question about this: Do some calculus theorems deserve to have their own tag? It is probably better to discuss these tags in general rather than having a separate post about each of them.

Do we need ? This tag was created not so long ago and at the moment it contains three questions.

If we are supposed to be consistent with the previous discussions about individual theorems from calculus, it should probably be removed: Tag proposal: mean-value-theorem.

I will point out that the tag for Intermediate value theorem was created by the same user, but almost immediately removed. And today the tag was created in this question.

If it would be better to start a separate discussion about tags named after theorems (or, more specifically, tags named after theorems from calculus) than discussing the tags separately, we can certainly start a new thread.

  • Not at all. That is bad form, and I think the user could use a talking-to from the mods. – Cameron Williams Mar 31 '17 at 17:23

I suggest to remove (or even blacklist) the tag. The problem with this tag is that the word projection is used in many various meanings in mathematics.

There is projection map in geometry and in linear algebra. In linear algebra we also have projection matrix. The term projection is used in connection with Cartesian products and equivalence relations. (And also for products and quotients of various spaces or algebraic structures. For example, projection from a topological space to a quotient space.)

Keeping all these meanings under the same tag would probably make it too heterogeneous. If some of these meanings needs tag, then a tag which would be more specific can be created. (For example, the tag name could specify that the tag is intended for projections in linear algebra.)

This tag has been created and removed several times in the past.1 However, I did not found previous discussions about this tag on meta.

There already exist separate tags and . And also which seems somewhat similar and might also be problematic - I have made a separate post about the (map-projection) tag in this thread.

1See this SEDE query. The first occurrence found in this way is from 2012, but it only lasted for a few days. Creation of this tag has been mentioned in tagging chat room in January 2017 and again today.

Currently, the tag seems to be used for both the divergence of vector fields and the divergence of a sequence/series/integral. There is no tag-wiki. It currently has 307 questions.

It seems to me that the tag should not be applied to both. In particular, I don't think it's necessary to have a tag about divergence in the second sense, since there is already a tag (with about 10 000 questions) and a tag (with about 1000 questions).

I suggest editing the tag-wiki and renaming the tag (as suggested by Martin Sleziak in the comments) to restrict to the divergence of vector fields, and editing the tag out of the questions about divergence of series or others.

Note that there has already been a question about this tag, but the solution suggested by Daniel Fischer is different from my suggestion above. I think a tag about divergence of vector fields could be useful, which is why I suggest we keep it; but I am not opposed to Daniel's suggestion either.

  • 2
    Perhaps we could then create a tag with more descriptive name, like (divergence-vector-calculus) or (divergence-vector-field). This might reduce the number of mistagged questions. (Many users do not read tag-excerpts.) – Martin Sleziak Aug 9 '17 at 9:08
  • @MartinSleziak Good idea, I've added this to my answer. – Arnaud D. Aug 9 '17 at 15:25
  • Or (divergence-operator) – barto May 27 at 19:11

There are currently three different tags for different kinds of graded algebraic structures: , , and . While these are different kinds of structure, they are closely related and I don't think the ideas involved in thinking about them are distinct enough to warrant distinct tags. So I would propose that a single more general tag (maybe or ) be created, and , , all be made synonyms of it.

If graded rings and graded modules are considered distinct enough to keep as separate tags, I would still say at least that and should be synonyms.

Partly resolved. The tag is now removed from the system.

Proposal 1: Remove the tag .

This tag has no description. Mostly, it has been used, either wrongly, or as a synonym of the tag , or as a synonym of the tag . As such, it seems to have zero value, and even, possibly a small negative value.

Proposal 2: Remove the tag , considering that the subject corresponds to the tag .

Proposal 2 might be more debatable than Proposal 1 but, in my view, it has some strong motivations.

At present, the description of the tag mentions processes on the real line only (and even, the singular of the tag seems to indicate that what its authors had in mind is the homogeneous one-dimensional Poisson process only). Hence one could envision to keep it (once turned to , plural) for questions about one-dimensional Poisson processes, and to use the tag for questions about multi-dimensional processes and/or non Poisson point processes of any dimension. Except that no expert thinks of the name "Poisson processes" as referring only to one-dimensional processes.

Hence my suggestion to delete altogether and to retag the questions currently tagged with .

Currently tagged : 312 questions. Currently tagged : 25 questions.

Do we need the tag ? It was created recently in this question by Michael Hardy. (I have added , which I consider a good fit for that question.) The tag-info is empty at the moment.

This tag is similar to , previously discussed here and then removed. And it is also somewhat similar to tag, which is blacklisted (see here).

Another related past discussion on meta is Tag for a single algebraic equation?

The tag-creator also asked in the past about somewhat related tag: Another reason why the (algebra) tag should be allowed.

Since similar tags have been repeatedly discussed on meta or even created and removed in the past, I decided to ask on meta rather than simply remove the tag.

  • I think [system-of-equations] is strange, too. [equations] is better. – Takahiro Waki Apr 29 '17 at 6:33

The tag has been created recently. The tag-info is currently empty. Do we want/need this tag?

I'd say that past discussions on meta indicate that tags are not based on level/difficulty of the question, but on the content. For example: Should we require a tag that which specifies difficulty of a question? Similar tags have been removed in the past: Why is there an elementary-geometry tag?

Admittedly, is an exception, but there are some reasons why to keep questions about very basic stuff concerning sets separate. Moreover, the tag-wiki does a very good job in listing the topics which belong under this tag and there are several users dedicated to keeping the set-theory tags in shape, which is probably one of the reasons why it works well.

There is also the tag , but there is no clear consensus on what belongs under this tag: How to differentiate between (elementary-number-theory) and (number-theory)

I suggest removing as a synonym for . I would favor as an own tag. But I am not sure whether this would result in a tag with two big use cases in wildly different areas. So I would like to discuss this.

Not every question about natural numbers is about number theory. I often used it in the context of logic and model theory (Peano arithmetic). This resulted in readers coming from the tag to ask about basic abbreviations PA, ZFC, etc.

  • 2
    There is a tag peano-axioms. Could this, or a modification thereof cover your use case? I am afraid natural-numbers will not work well as a tag. – quid May 15 '17 at 20:03
  • @quid This could do it. However, I still think natural-numbers is not a good synonym of elemntary-number-theory – M. Winter May 15 '17 at 20:40
  • Yes, I agree. The synonym should go. It is a very old one; it may have made sense then, but now I think it creates more problems than it solves. – quid May 15 '17 at 21:12
  • 1
    I have collected links to some previous discussions about (natural-numbers) tag here. – Martin Sleziak May 15 '17 at 21:43
  • 1
    I don't recall the old discussion (may be it was before my time?). Anyway, the danger is probably that we have freshmen and/or high schoolers tagging natural-numbers when they should use elementary-number-theory. Possibly also when diophantine-equations or induction would be more appropriate. – Jyrki Lahtonen May 16 '17 at 7:10
  • 1
    The syn is no more. – quid Feb 18 at 15:37

Resolved: There is now a synonym with (square-numbers) as the master tag.

It seems that the tags and are about the same thing, so creating a synonym $\to$ seems reasonable to me. In fact, there already is tag synonym suggestion (by barto).

There was a bit related discussion in this answer. (See revision history - mainly the first revision - and comments.)

The tag was created in July but it also had a short-lived previous incarnation in 2015. (Found using this SEDE query, which is mentioned in arjafi's answer.)

The tag was recently created (and currently houses two questions).

It is not necessarily a bad tag. But the questions on Borel sets have a fairly distinctive division: topology, measure and probability, and descriptive set theory.

So on its own it might result in people using only that tag, thus having lower exposure to their question.

It also adds very little to the search function, since "Borel" is fairly easy to search for, and you cannot talk about Borel sets without mentioning the word "Borel".

So I am a bit torn as to whether or not this tag is useful.

  • I have added tag-excerpt and tag-wiki which at least mention that it is useful to add also other tags. (Many people ignore tag-excerpts, but at least some users might notice it.) – Martin Sleziak Feb 17 '17 at 16:19
  • I take from this action that you think this tag is worth keeping? – Asaf Karagila Feb 17 '17 at 17:18
  • No, it was not meant as a support for keeping tag. (I am neither clearly against nor clearly for the tag. I can see that it might be useful - if pressed to make some decision I would lean towards keeping.) I think that even if the tag is later removed and the information in the tag-excerpt only helps user during the (possibly short) period while this tag exists, it is still useful that it is included there. – Martin Sleziak Feb 17 '17 at 17:22
  • 1
    Perhaps in connection with (borel-sets) tag, it might be worth mentioning that (sigma-algebra) was made synonym of measure-theory a few years ago. See also here. – Martin Sleziak Feb 18 '17 at 6:49

Resolved. Mis-spelled tag merged into

Just saw the embarrassingly misspelled ; please delete this tag and retag the questions as .

  • 1
    I think such mis-spellings are more a case for a flag than for a post in this thread. – Daniel Fischer May 17 '17 at 21:21
  • @J.M.isn'tamathematician In such cases, all that you need to do is retag. The tags which are not used in any questions are removed by a script once a day. See also: Deleting Tags after being created and Please delete misspelled (ananlysis) tag. – Martin Sleziak May 18 '17 at 6:04
  • @Martin, there were at least ten threads with the malformed tag, so I thought retagging en masse would have made not a few people grumble. As Daniel says, flagging would really have been the least distracting method, but I wanted a public record. – J. M. is not a mathematician May 18 '17 at 6:43
  • @J.M.isn'tamathematician My bad. I thought that it was a single occurrence. (When I saw your post the tag was already gone, so I did not have possibility to check is.) I should have guessed that it is very unlikely not to know about removal of tags in this way for somebody so active on meta as you. Sorry for that. (If you think we should remove the last three comments - since they are not really relevant after this clarification - feel free to ping me in chat.) – Martin Sleziak May 18 '17 at 7:53

In my interest in mapping between a rectangle and its projection resulting in a quadrilateral I have learned of the important concept "homography". There are many homography questions here on the site but there is currently no "homography" tag.

Would somebody like to create this tag? If not, which tag should I use instead?

If you decide to create it, just search for one or more questions about homography and add the tag to that, those questions.

A very random sampling of homography questions, not necessarily the best in any sense:

I included a few that don't use the word "homography" anywhere on the page, perhaps because it's not a term everybody knows even when they come across such a problem for the first time, or possibly due to my own lack of deep understanding.

  • 2
    Tags cannot exist without being associated with at least one question. If you can point out some questions in your post above for which you feel a homography tag might be suitable, it would make this process easier. – user642796 Aug 19 '17 at 5:27
  • My god there's at least dozens. I'm on a temporary connection so I'll just add some random ones rather than necessarily the best ones ... – hippietrail Aug 19 '17 at 6:26

Is there a point to the tag? It seems to me that since we already have the and that is enough.

The current tag wiki is simply a statement of what is a fixed point in the excerpt; and "I think it can merged to" in the wiki itself.

I'm open to argument as to why this tag is useful, but it seems to me that the wiki is probably on the nose here (even if that was not the place for such statement), and this should be merged into .

  • It seems that the tag was created in March. (Sorry, in the flood of new tags I was not able to make post on meta for each one of them.) A reasonable question would be whether to create a synonym (in one direction or another). This would prevent this tag from being created again. – Martin Sleziak Aug 30 '17 at 18:17
  • 1
    I'll used this oportunity also to get some attention to another post about tags related to fixed points - namely (fixed-point-iteration) and (banach-fixed-point). – Martin Sleziak Aug 30 '17 at 18:19

In connection with the discussion of projection tag I have noticed that there is the tag called .

This tag was very likely created with cartography in mind. The the first occurrence found by this SEDE query is the question How do great circles project on the mercator projection?. To clarify the distinction I will quote from the Wikipedia article on map projection: "More generally, the surfaces of planetary bodies can be mapped even if they are too irregular to be modeled well with a sphere or ellipsoid; see below. Even more generally, projections are the subject of several pure mathematical fields, including differential geometry and projective geometry. However, "map projection" refers specifically to a cartographic projection."

However, if you look at how the tag is actually used, there are currently 22 questions, most of them seem to be about projection in the sense of linear algebra. (There are only two questions which are also tagged cartography.)

What should be done with the tag ?

  • Clarify in the tag-info that it is intended for cartographic projection and retag the existing questions in accordance with this?
  • Remove the tag completely since it is likely to be ambiguous?
  • Rename the tag in the way that it becomes less ambiguous - for example, or ?
  • Embrace the chaos and use it for both meanings - projection in cartography and projection map?

If we keep the tag, it would probably be useful to create tag-excerpt and tag-wiki clarifying how the tag is supposed to be used.

The tag was created not too long ago and it started growing rather quickly. (Currently it has 24 questions.)

Previously there were separate tags and which were removed after discussion on meta. See here: Tag management 2016.

I suggest to remove the new (upper-lower-bounds) tag. Or has the opinion of the community changed since the previous discussion about rather similar tags?

  • Ok to remove I think. Is there something not covered with enough specificity by inequalities, asymptotics and estimation? (the last one being a candidate for pluralizing) – barto Jun 7 '17 at 10:15

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