Currently our $2$-groups tag concern about $p$-groups with $p=2.$ However there is another well established notion of $2$-groups in algebraic topology/homotopy theory about $2$-dimensional higher groups. In fact, it generalizes to $n$-group for any $n\in\mathbb{Z}.$ This is a very unfortunate coincidence of terminologies. But usually it does not confuses people in day-to-day mathematics as they belongs to two quit far away fields.

As far as I know, currently we don't have questions about the second notion of $2$-groups and therefore it does not make sense to construct one immediately (but we may need to do so one day). What I am interested in is, how can we create a new tag for this second notion without destroying the existing tag and without making a confusion?

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    $\begingroup$ Something to keep in mind if the need arises. $\endgroup$
    – hardmath
    Mar 8, 2021 at 5:00
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    $\begingroup$ Maybe you could ask and answer a question in the second category, just so a tag can be created for it $\endgroup$ Mar 8, 2021 at 18:13
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    $\begingroup$ @BenjaminWang: I am curious about the process of making a such tag while there is another tag with the same name for on a different thing. $\endgroup$
    – Bumblebee
    Mar 8, 2021 at 21:37

2 Answers 2


I think 2-groups-higher-categories and n-groups-higher-categories would clearly signal what they were talking about. I'm not sure anyone is asking questions about these, though.


It is not possible to have two tags with the same name. There are a few options to work around such things.

For example we have to signal what type of divisors we mean.

One can also group things together to disambiguate, for example "divisors-and-multiples" would convey what divisors are meant as well.

For the current case, frankly, I don't see a need for the 2-groups tag, p-groups should suffice.

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    $\begingroup$ While $2$-groups are technically a special case of $p$-groups, their properties are very different from other $p$-groups of odd order, and are generally considered to be a different topic by group theorists. They are treated with different books, for example. $\endgroup$
    – Alexander Gruber Mod
    Mar 9, 2021 at 19:48
  • $\begingroup$ Fair enough, I still don't think that tag is overly useful. I mean it seems to get one or two questions a year or so. $\endgroup$
    – quid Mod
    Mar 9, 2021 at 23:17
  • $\begingroup$ yes, conceptually it is distinct, but it doesn't seem to be very active. I wouldn't be opposed to repurposing it for algebraic topology if that topic has more interest. $\endgroup$
    – Alexander Gruber Mod
    Mar 9, 2021 at 23:37
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    $\begingroup$ If we need the other I'd go for "higher order groups" or some such thing. $\endgroup$
    – quid Mod
    Mar 10, 2021 at 1:06
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    $\begingroup$ I'd support that. $\endgroup$
    – Alexander Gruber Mod
    Mar 10, 2021 at 3:11

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