Tag management 2015 [duplicate]

Tags need a regular cleanup. This is a customary thread for tag synonyms etc.

Rules of the game are basically the same:

• 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;
• let's wait a couple of days before implementing a suggestion;
• after the problem described in an answer is resolved, please edit it to say so.

(Of course if a proposal requires an extended discussion you can post it as a separate question.)

• A possible tool for finding not-so-great tags: Tags by percentage closed. I hypothesize that some tags, by their mere existence, encourage poor and/or offtopic questions; this query attempts to sort tags by badness of questions. – apnorton Aug 4 '15 at 16:51
• @apnorton I guess great minds think alike! Though mine is a horrible SQL mess (I think because I also wanted to have the overall % of closed questions, I don't remember). – Najib Idrissi Aug 4 '15 at 16:52
• @NajibIdrissi I swear I searched before writing mine! :P – apnorton Aug 4 '15 at 16:53

Why is the tag for useful?

I don't see it. I think it should be removed, although it's not as bad as the recently blacklisted .

• I thought I got rid of this tag once already. – user642796 Sep 27 '15 at 5:53
• We have many questions asking whether some particular metric space is complete. Tag related to this would make searching for such questions easier. (Although probably (complete-metric-spaces) would be a better name.) – Martin Sleziak Sep 27 '15 at 8:10
• @Martin: I'm a bit with Arthur on this. I guess. – Asaf Karagila Sep 27 '15 at 11:57
• @Arthur: Maybe it's time to bump the tag creation privilege to 2000? :-) – Asaf Karagila Sep 27 '15 at 11:57
• @Asaf: I'd almost suggest bumping it up to ♣+CH. ;-P – user642796 Sep 27 '15 at 11:59
• @Arthur: Since CH implies MA trivially, the only way I'd agree is if Martin becomes a moderator and make all these decisions aximoatically. :-P – Asaf Karagila Sep 27 '15 at 12:09

I propose creating tag. Absolute continuity seems to be rather important notion in real analysis. It is closely connected to the Fundamental theorem of calculus. And it is closely related to several other important classes of functions - many of the important enough to have a separate tag on this site, such as , and .

We often have questions related to this notion. Just try to search for:

Resolved: Tag has been removed.

I was going to remove the tag from this question until I realized that there were a hundred questions related to this inequality. I am not too familiar with DEs: do people who are think this could use a tag?

• I've heard colleagues mention it multiple times and I've seen it in stochastic processes. I think it's probably safe to leave it as is. I think people who need it, it's a very good tag to have. – Cameron Williams Feb 3 '15 at 5:22
• Right, so I guess my question is whether it is worth creating tagging those 100 questions. – Eric Stucky Feb 3 '15 at 5:30
• Oh I see. I totally had the opposite understanding of your comment. I feel silly now. Reading comprehension is hard. I think it might be beneficial for sure. – Cameron Williams Feb 3 '15 at 5:32

I feel that we should remove tags like , and . They don't really help to organize. IMHO they basically just elaborate on the content of a specific question. If someone has a question about a Noetherian module, they'll probably just start with: "We have a Noetherian module $M$..." I said "tags like", because there are probably more tags of this kind that I haven't come across. To me these kind of tags are equivalent to using the tag "", instead of just .

If someone knows of more tags that elaborate on content of a specific question rather than organize, then please mention these in the comments, so we can get rid of them all in one swift move.

In addition, the same thing holds for:

• This is an extremely broad proposal. I think you should try to pin down what makes you say "They don't really help to organize. IMHO they basically just elaborate on the content of a specific question." More specifically, generally adjectives are not so great as tags, thus I think agree "noetherian" is not a good tag, I am not sure about the "ideals." – quid May 30 '15 at 17:02
• @quid To be fair, when a tag is to specific for a question is of course decided by an arbitrary line in the sand, differing per person. I just feel very strongly that a majority of people would agree with me on which side of the line these two belong. Also the number of followers of these tags does not speak in favour of prolonging their life span. In any case, you would surely agree with me that if they stay, they should be merged to one tag: (ideals) (based on your very well put "adjectives argument"). – gebruiker May 31 '15 at 15:40
• I don't know. The taxonomist tag is awarded at 50 questions tagged with a tag. I have no strong feelings either way it is just mainly that the proposal feels arbitrary in its scope. What about flatness or any number of other tags that are a lot smaller. – quid May 31 '15 at 16:04
• @quid flatness can also go if you ask me. For the same reasons basically. But that's just how I feel. – gebruiker May 31 '15 at 16:19
• There is now a separate question about the ideal-related tags: meta.math.stackexchange.com/questions/23012/… – Martin Sleziak Apr 12 '16 at 7:38
• @user26857 Looking at the votes on the new post, there are 22 upvotes on the answer for the synonym and 9 upvotes on the answer against. So definitely more people support synonymizing these tags with ideals. So maybe you could suggest a synonym. (After all, you brought up this issue again in comments on the main and you also made clear that you are for removing/synonymizing (maximal-dieals) and (prime-ideals).) – Martin Sleziak Apr 22 '16 at 5:34
• @MartinSleziak I've proposed to keep only the ideals tag, and remove the other two. – user26857 Apr 22 '16 at 7:41
• @user26857 Making the two tags synonymous with ideals basically does that with two additional advantages: 1) The users cannot create the two tags anew. 2) All posts which are currently tagged by any of those two tags would be now automatically tagged ideals. In any case, if you have some different suggestion from the two posted in the linked post, you can post another answer. And if needed, we can discuss this further in chat. – Martin Sleziak Apr 22 '16 at 7:47

I suggest to delete the tag as too specialized.

• I don't see why a tag used on 2 (two) questions requires any action. Not being an expert I'm also not sure if the tag is actually bad. – Grigory M Jan 2 '15 at 20:02

Someone recently created . While I can appreciate the intent, I guess I don't really see the point: pretty much any question related to the Klein bottle will have the words "Klein" and "bottle" in quick succession and can be easily searched (which may not necessarily be the case for other spaces that have standard notations, eg. the projective spaces).

I also don't think the Klein bottle is so fundamental that it deserves a tag of its own, and there cannot be tag for every named, somewhat interesting mathematical object. Imagine if we had tags for the Bernoulli distribution in probability, the Monster group, the Euler characteristic or the monoïdal tricategories... At some point I think tags would become more redundant than useful.

• I think most of these arguments would also apply to moebius-band, though there's the difficulty that it's sometimes called "Möbius/Moebius/Mobius band/strip". But in general I think tags should be more like categories. So eg. surfaces could be a better option. – Najib Idrissi Mar 9 '15 at 12:30
• i agree... i just saw 4 (old) klein bottle questions on the front page and was wondering what was going on... someone is bumping all of the questions by adding the tag – Tyler Mar 9 '15 at 22:58
• I actually disagree with this suggestion. I actually feel that highly focused tags are often better than many of our wishy-washy tags such as compactness, where it is often difficult to determine if a question really falls under the tag (and is therefore used inconsistently). At least with klein-bottle it should be easy to determine whether a question actually is about that concept. – user642796 Mar 10 '15 at 7:19
• @ArthurFischer My point is precisely that it's so easy that the tag becomes useless: someone looking to answer questions about the Klein bottle can just search for these words. (Though maybe someone is so uninterested by Klein bottles that they want to ignore the tag...) – Najib Idrissi Mar 10 '15 at 15:34

The tag was created.

It seems to me that this is a natural synonym of .

• I agree that it is a subtag of modular-arithmetic but I would not make it a synonym, as it facilitates searching and doesn't seem too localised not to stand alone. – Bart Michels Apr 13 '15 at 20:28

The tag is created recently. Do we need such a tag? I suggest to make it a synonym of (or ) or just remove it.

• I would rather make it a synonym of transcendental-numbers. – Najib Idrissi May 27 '15 at 7:48
• I just realized that my previous comment is inconsistent with the fact that we have a tag rational-numbers and a tag irrational-numbers... Something I don't really find optimal. – Najib Idrissi May 27 '15 at 9:30
• We'd have to ask us whether there is a significant amount of questions about algebraic numbers that are not about transcendental numbers, and vice versa. (This is the case with rationals/irrationals; e.g. questions regarding rational solutions to diophantine equations, representations of rational numbers; the topic of diophantine-approximation). If there isn't, I suggest to merge both tags into algebraic-transcendental or something. – Bart Michels May 27 '15 at 10:09
• I would find it possibly confusing to have algebraic numbers as a synonym of transcendental numbers; it could result in weird tagging. Somebody asking something about $Q[\sqrt{-7}]$ might tag algebraic-numbers, but this should not be related to transcendental numbers at all. If anything I would synonym it with algebraic-number-theory – quid May 27 '15 at 14:06
• It seems that the tag was removed. – Martin Sleziak Jun 3 '15 at 8:07
• @MartinSleziak : Yes. Indeed I am not sure if it is appropriate to do so (un-tag that only question, so as to delete the tag) – user99914 Jun 3 '15 at 8:11
• If this is what you are asking, removing tag from all questions is precisely the way how to delete the tag: meta.math.stackexchange.com/questions/1200/… If you are asking whether the discussion here show sufficient support for the tag removal to go ahead with it - the only thing I can say is: Use your best judgement. – Martin Sleziak Jun 3 '15 at 8:15

Do we need ?

It passes the "initial Google test", and it seems to be a subset of order theory. Currently there are two questions, both written (and tagged) by the same person. And this seems like a tag that will be rife with mistagging by people who ask questions like "What is the domain of ..."

The latter is not a reason not to have a tag (just look how many do this with logic and set theory tags!), but since domain theory is not a particularly active topic on this site, it means there will be less people monitoring the tag and less people will be maintaining its correct use.

So I'm asking, do we really want this tag, or should we forfeit and remove it?

It was brought up in this thread as a side remark that we have both and .

It would appear to me that the latter can be merged into the former without much trouble.

• To me the tag (computer-algebra-systems) seems to be more specific. For example, Geogebra, Google calculator, R and S are (math-software) but they probably aren't computer algebra systems. (judging from the very little I know about Geogebra, R or S. ) – Martin Sleziak Feb 1 '15 at 17:16
• I agree with Martin. I'd say it might even depend on the question. When I'm using Sage to do computer algebra (under the hood via Maxima), that should be on topic for CAS. When I use Sage to do numerical optimization, or statistical analysis, or draw geometric figures, that's not sp much CAS but still computer algebra. So I'd say keep both tags, but in the math-software wiki, don't fix the distinction on the software alone. – MvG Feb 6 '15 at 8:29

Update. Martin Sleziak's suggestion has been taken up, and (limits-without-lhopital) has been made a synonym for .

Change to "limits-without-lhopital". Change tag wiki text from L'Hospital to l'Hôpital.

• "In the 17th and 18th centuries, the name was commonly spelled "l'Hospital", and he himself spelled his name that way. However, French spellings have been altered: the silent 's' has been removed and replaced with the circumflex over the preceding vowel. The former spelling is still used in English where there is no circumflex." Wikipedia – user147263 Jan 3 '15 at 0:44
• As for tag wiki change, you can go ahead and suggest an edit yourself; they are edited by users like other posts, except there is a higher threshold for approving the edits. – user147263 Jan 3 '15 at 0:46
• I am not sure the change is needed, but having both names (as synonyms) will probably do no harm. – Martin Sleziak Jan 3 '15 at 9:39
• Similar (Kähler), in the end they were made synonyms. – Najib Idrissi Jan 3 '15 at 10:27
• I will add a link to a related questions: meta.math.stackexchange.com/questions/20542/… – Martin Sleziak May 31 '15 at 5:57

The tag looks very narrow to me. Only nine questions even mention the word at all. It seems to me that sedenions are only ever thought about when one thinks about the Cayley–Dickson construction.

I suggest creating and making a synonym of this. Many (almost all) questions mentioning sedenions or mentioning the word are already about the construction ("what lies beyond quaternions?", "what do we lose when going to sedenions"... basically).

The case of is a bit more debatable: 56 questions. As far as I know octonions don't really have many more uses (see this or this). is fine for me, they are useful on their own and much more common. If this suggestion is implemented, we could have a discussion about making a synonym too.

• I have favourited (octonions) and I'm certainly against deleting the tag. BTW citing answers to question about 'real-world' uses of something to prove it mathematical uselessness is downright ridiculous (can you think of many 'real-world' uses of etale cohomology or BGG-resolution, I wonder?). – Grigory M Jan 4 '15 at 10:59
• @GrigoryM I cited that because the only mathematical use of octonions I know is the Hopf invariant problem, and even then it's only tangentially relevant. Anyway, maybe I should have separated the two suggestions (octonions and sedenions)? I tried to make it clear that the suggestion is mostly about the tag sedenions, but I guess that didn't work out. – Najib Idrissi Jan 4 '15 at 11:01
• Posting two suggestions in one answer is always inconvenient indeed. But more importantly... – Grigory M Jan 4 '15 at 11:02
• ...to quote Behaviour: «there are perfectly sensible tags (...) [s.t.] few users read or vote on posts in the tag. This does not make the tags useless; on the contrary, it helps the few users knowledgeable in those subjects find and answer the questions they are interested in.» – Grigory M Jan 4 '15 at 11:04
• @GrigoryM Did you read that part "Many (almost all) questions tagged sedenions or mentioning the word are already about the construction ("what lies beyond quaternions?" basically)." or that part "making sedenions, and even possibly octonions a synonym of this"? – Najib Idrissi Jan 4 '15 at 11:05
• Okay, perhaps for (sedenions) your suggestion makes sense. – Grigory M Jan 4 '15 at 11:08
• @GrigoryM I edited my suggestion. – Najib Idrissi Jan 4 '15 at 11:09
• ...As for uses of octonions in topology and geometry, algebra and number theory see John H. Conway. On Quaternions and Octonions, Baez. Octonions and (ample) bibliography there – Grigory M Jan 4 '15 at 11:20