Since it is a new year and the old Tag Management question has already over 70 answers, it is time for a 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.

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.

  • $\begingroup$ I like how this is a game, but you didn't explain the points system. $\endgroup$ – Simply Beautiful Art Sep 20 '16 at 23:59
  • $\begingroup$ Maybe it's time to start a new thread, and the first answer there should encompass the still-open issues from this thread? $\endgroup$ – Asaf Karagila Jan 15 '17 at 8:38
  • $\begingroup$ @AsafKaragila Should I copy all the still-open answers onto the new thread in multiple different answers? $\endgroup$ – suomynonA Jan 17 '17 at 1:36
  • $\begingroup$ @suomynonA: One answer with links should suffice. Thanks! $\endgroup$ – Asaf Karagila Jan 17 '17 at 4:09
  • $\begingroup$ @AsafKaragila Take a look here, looks good? $\endgroup$ – suomynonA Jan 17 '17 at 4:51

64 Answers 64


I was considering creating (l'Hospital's-rule). Is searching for these questions sufficient?

  • $\begingroup$ We already have limits-without-lhopital, FYI. $\endgroup$ – Najib Idrissi May 24 '16 at 17:10
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    $\begingroup$ @NajibIdrissi yes, I know, but the proposed tag is the opposite. $\endgroup$ – ahorn May 24 '16 at 19:33

Resolved: The tags have been removed.

The tags , and have been created not so long ago (they are still in the list of new tags.) A natural question is what to do with these tags.

So far the questions about these topics were typically tagged and/or .

Considering that we have many questions about these topics, I guess that these tags might improve searching. So I would be in favor of keeping these tags. (I.e., downvotes on this post should be interpreted "these tags should be removed".)

The only disadvantage I see that some questions will have too many tags as a result of this. (For a questions about injective functions, the tags , and would be suitable, which already takes three of five possible slots.) However, I think that these tags will be mostly used for basic questions, so probably not many additional tags will be needed.

Of course, if we keep the tags, we will have to add them at least to some older posts. But I think that it will be not that difficult to add the tags gradually at least to the most important ones. I guess that such questions can be found among frequent questions tagged functions and maybe to a lesser extent among frequent questions tagged elementary-set-theory

At the moment, there are only a few questions having these tags. So if the decision will be to remove the tags, it would not be a big problem. (Only a few posts will be bumped.)

A third option would be make these tags a synonym of some existing tag. This would prevent creating the tags repeatedly again and again. But if we choose this possibility, I am not entirely sure what tag should be chosen as a synonym. If I had to select one, I would probably go with .

  • $\begingroup$ I don't see how any of these three tags help, other than causing new users who have no idea how to tag their questions use them instead of proper tagging. But unlike the case where someone uses [real-analysis] or something like that, nobody really follows these new tags, so nobody really notices the questions and tags them appropriately. $\endgroup$ – Asaf Karagila Jul 9 '16 at 7:04
  • $\begingroup$ I have also pinged the tag creator to let them know about this thread. $\endgroup$ – Martin Sleziak Jul 9 '16 at 7:44
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    $\begingroup$ I should probably add that I removed similar tags in the past (if my memory serves me right, those were "bi-/in-/sur-jection" named, but who can remember these things?) and I would have removed them judiciously if I had noticed them before you made this post. The real question, now, is whether or not anyone else is going to weigh in. $\endgroup$ – Asaf Karagila Jul 9 '16 at 9:47
  • $\begingroup$ @AsafKaragila If we want to see whether somebody else will comment or at least vote, we should wait at least for a few days. (Not everybody reacts within hours of posting.) But I certainly agree that tag-related posts often do not get enough feedback and if they do, the tags can grow in the meantime. If you want to remove these tags preemptively before they become large and removing them would cause bumping many posts, I will not object to it. As list of all taged questions and tag-wikis are saved in chat, it would be relatively easy to recreate the tags (if that is community consensus). $\endgroup$ – Martin Sleziak Jul 9 '16 at 10:06
  • $\begingroup$ I guess we can wait a couple of days, at least after the weekend, before concluding that nobody else cares enough to weigh in. :-) $\endgroup$ – Asaf Karagila Jul 9 '16 at 10:07
  • $\begingroup$ BTW what would you think about synonyms for this tag with (functions) as the master tag? (And I have made a few comments which are vaguely related to this discussion in tagging chat room,) $\endgroup$ – Martin Sleziak Jul 9 '16 at 10:25
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    $\begingroup$ That is an option. Although truth be told, I'm not a huge fan of the functions tag in general. $\endgroup$ – Asaf Karagila Jul 9 '16 at 10:30
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    $\begingroup$ Nothing happened, and the weekend passed with additional day for people to voice their opinion. I'm going to remove these tags now. If they pop up again (and I haven't been ahead of you in removing them immediately), we'll talk about synonymizing them. $\endgroup$ – Asaf Karagila Jul 12 '16 at 5:02

I created a new tag yesterday. I was not aware of this thread.

It is called and has this tag wiki:

"This tag is for questions about birth and death processes. These processes are a special case of the continuous-time Markov process where the state transitions are of only two types: "births", which increase the state variable by one and "deaths", which decrease the state by one and they are used to model the size of a population, queuing systems, the evolution of bacteria, the number of people with a disease within a population etc."

I created the tag because I thought it was reasonable to have such a tag when there are tags for poisson process and levy process. After all birth and death processes are widely used and the poisson process is also a markov process (and also a levy process).

Now when I have found this thread I just want to know if you think this tag is too specialized and/or too closely related to other tags?

If that is the case I remove the tag.

  • $\begingroup$ Having given it some time, it seems like people are asking questions about it other than just you, so it seems fine to me. I could certainly imagine a scenario where someone may be interested in viewing an aggregation of questions about this topic. $\endgroup$ – Alexander Gruber Jun 18 '16 at 16:55
  • $\begingroup$ You may, however, want to add a disambiguation that the tag should not be confused with birth-death diagrams in persistent topology. $\endgroup$ – Alexander Gruber Jun 18 '16 at 17:00

I suggest to add a tag (yes-or-no), used for question that are meant to receive a Yes/No answer, without need of further explanation. The standard question of this tag could be of the form "Is this fact/implication true?"

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    $\begingroup$ I disagree. Just because the author of question doesn't need an explanation does not mean nobody else needs it. Good answers are substantiated; bad answers are not welcome. $\endgroup$ – user147263 Jan 13 '16 at 5:00
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    $\begingroup$ This would be a meta-tag. Despite the fact that a few such tag exists and are allowed, it is advised not to create new ones, unless there is a very good reason to. See: meta.math.stackexchange.com/questions/2498/the-meta-tags $\endgroup$ – Martin Sleziak Jan 13 '16 at 8:00

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