I am a bit unsure if this should be posted here or in Mathematics, but I try it here.

I was surprised to see that there was no "Kleinian groups"-tag at Mathematics and Mathoverflow. I would like to know why. Is it because it has been considered but turned down, or has it never been considered?

If it is the former, I would very much like to know why. It is after all a well established and well defined mathematical subject with over a century of history and, given the interest for fractal images and their background/way of rendering, of some public interest.

If it is the latter, I would like to suggest an addition of "Kleinian groups" to the collection of tags, both for Mathematics and Mathoverflow.

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Jan Olav R is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
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    $\begingroup$ A quick search suggests that there are 64 questions about Kleinian groups on math.stackexchange and 135 on mathoverflow. These all seem to be tagged with some combination of hyperbolic-geometry and geometric-topology though other tags appear as well. On a site with actually hundreds of thousands of questions, are these numbers enough to warrant a special tag? $\endgroup$
    – postmortes
    Commented Jul 9 at 10:30
  • $\begingroup$ @postmortes That is a fair point. But there are existing tags with less hit on searches, like ackermann numbers (on overflow) and acyklic orientations. Do you disagree with me that it is a well-established mathematical subject? $\endgroup$
    – Jan Olav R
    Commented Jul 9 at 11:35
  • $\begingroup$ it is after all in MSC. (sorry for double commenting, I was too slow with the editing.) $\endgroup$
    – Jan Olav R
    Commented Jul 9 at 11:42
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    $\begingroup$ I guess it is self-evident - but I will still point out that this is not a right place to discuss tags on MathOverflow; they have their own meta. (So we should stick with Mathematics.) @postmortes How exactly did you get 64 questions. I only get 33 results. Perhaps you searched for both questions and answers? $\endgroup$ Commented Jul 9 at 12:02
  • $\begingroup$ @MartinSleziak ah, yes, you're right, I wasn't careful enough! Sorry -- and thank-you for double-checking :) $\endgroup$
    – postmortes
    Commented Jul 9 at 12:06
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    $\begingroup$ One should keep in mind that there are only five slots for tags. If we created too many tags for very specialized topics, there will be questions where more than 5 of the existing tags are suitable. I will add that I did not find older occurrences of a tag for Kleinian groups - I posted the SEDE queries in the tagging chatroom $\endgroup$ Commented Jul 9 at 12:07
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    $\begingroup$ @JanOlavR I'm not agreeing or disagreeing with you. Comments are for improving questions and it seems like your question would be better answerable by the community if you provided a modicum of concrete data, like the number of questions you're proposing to tag and explaining why the existing tags/search options aren't good enough. You are free to ignore everything I write. $\endgroup$
    – postmortes
    Commented Jul 9 at 12:07

1 Answer 1


Thanks for posting here before unilaterally creating a new tag. I'm unfamiliar with the subject area and don't have a strong opinion one way or the other about its creation. Here are some topics that often come up when doing tag management (see this Meta Math SE post for examples).

What is the population of existing (or prospective) Questions that would use this tag like? In part this could be addressed by proposed text for the tag usage "Text Info". Clicking on Learn More for any tag (see Tags menu item at left on the desktop version of an SE site) will give some examples. See also the Answers for Questions about tag-wikis at meta.

A proposed tag wiki is also helpful for such discussions. Often an advanced topic like Kleinian groups will involve several variant definitions found in the literature. The tag wikis admit markdown content for linking to web resources that delineate such variations and relationships among them. Here for example there seems to be a serviceable Wikipedia entry as a link.


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