Excerpt for tag says at the moment:

Elementary questions involving functions.

From this it is not entirely clear what kind of questions the tag is intended for. But I definitely think that some question tagged by this tag do not correspond to this description. Maybe expanding tag-excerpt/tag-wiki could help but I did not want to this without discussing the issue here first.

I'll post an answer about what I think was the intended use; please, if you think that I've forgotten some important things or if you have better suggestions, please post them as answers.

I propose that if we reach some consensus about when this tag should be used, we can edit tag-excerpt to reflect this. (In order to help users to use this tag correctly.)

  • 4
    $\begingroup$ I should mention that complete removal of this tag was discussed at meta before: meta.math.stackexchange.com/questions/715/… $\endgroup$ Dec 9, 2011 at 14:01
  • 6
    $\begingroup$ Huh, so in the first few weeks, when there were 7 questions tagged functions, there were already no compelling reason to keep that tag. And somehow it is still alive? Amazing. I had assumed it was a holdover from the "olden" days. But it seems I am not quite correct. $\endgroup$ Dec 9, 2011 at 14:11

1 Answer 1


Tag is intended for elementary questions about functions, which include:

  • definition and basic properties of functions (domain, codomain, inverse function, bijective/injective/surjective functions, image and preimage of a set, even/odd functions etc...)
  • names and notations for various functions
  • For questions about graphs of function, we have tag. But this tag can be combined with .

Obviously, the questions in the above areas will probably have large intersection with and ; but not all questions tagged fall under these two tags.

For more specialized topic, such as continuity, limit, derivative, maxima and minima, functional equations... we have different, more appropriate tags.


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