I have noticed that tag was created again. According to list of new tags it was created Jun 9 at 7:55. There are currently 3 questions having this tag.

I was not able to find a discussion on meta where this was decided, but I know that this tag was not used. Since 2013 it had tag-excerpt saying: "Deprecated; please use a more specific tag." (Another example of deprecated tag is - at least according to the tag-excerpt.) The tag (topology) has been completely removed in 2014.

What should be done about the topology tag if it reappears again, like it did now? Should we try to do something to prevent it from being created again?

  • Should we simply rely on the fact that many users of this site know that this tag is deprecated and if it is created again, some users will remove the tag from the questions (and in the next 24 hours it will be removed from the site)?
  • Should some reasonable tag-synonym be created, for example, $\to$ ? (This would prevent users from creating this tag as a new tag; if somebody will use it, the tag will automatically be changed to the master tag. The disadvantage is that some users might not notice that the tag they typed in was changed to the synonym.)
  • Should the moderators request the SE team to blacklist this tag? (The obvious disadvantage is that users trying to use this tag might wonder why the tag called topology is not allowed. However, it is possible to customize the messages shown when a user tries to make a post containing some blacklisted input, see here and here.)

EDIT: Now the tag has been already removed from all questions. So in 24 hours the tag should disappear completely, unless it is used in another question.

But the question whether something should be done to prevent this tag from being creating again remains.

  • 4
    $\begingroup$ I miss quid from these discussions... $\endgroup$ Commented Jun 20, 2016 at 15:34
  • $\begingroup$ For me, topology says "2 questions tagged topology", but only one is shown. $\endgroup$
    – Stefan Kohl Mod
    Commented Jun 20, 2016 at 21:06
  • $\begingroup$ @Stefan: you can see the other question in the RSS feed for the tag. It got some downvotes and was removed by the author, but not before being included in the feed, which is what gets counted. $\endgroup$ Commented Jun 20, 2016 at 22:04
  • $\begingroup$ Ah, the second one is this deleted question. -- I wonder why deleted questions are counted, but not listed. $\endgroup$
    – Stefan Kohl Mod
    Commented Jun 21, 2016 at 12:13
  • $\begingroup$ @StefanKohl This is only tangential to the issue at hand. But since I was curious too, I have asked at meta.SE: meta.stackexchange.com/questions/280473/… $\endgroup$ Commented Jun 21, 2016 at 12:16
  • $\begingroup$ Meanwhile the count appears to have been corrected. $\endgroup$
    – Stefan Kohl Mod
    Commented Jun 21, 2016 at 12:23
  • $\begingroup$ As I do not have 10k+ reputation I cannot view deleted questions. Just out of curiosity, can you checke whether the deleted question has been retagged or whether it was corrected independently of this @StefanKohl? Thanks! $\endgroup$ Commented Jun 21, 2016 at 12:25
  • $\begingroup$ The question was not retagged, and has still the topology tag. $\endgroup$
    – Stefan Kohl Mod
    Commented Jun 21, 2016 at 12:32

2 Answers 2


The SE team has the ability to blacklist tags. The most efficient way to request this is probably to list all tags that should be blacklisted into a single (new) meta post "Blacklist [topology], ..." and where possible link to the meta posts that support this blacklisting. (As far as I can tell none of the links in your post why the tag should be disallowed.)

Tag synonyms are an efficient way of making sure that variant spellings are the same tag, e.g. . I think that is a reasonable synonym.

It might not be so straight-forward for (which still has 533 questions, though).

Users are able to create suggestions for synonyms, but it's probably easier to have a moderator create the synonym.


One of the possible suggestions (both in the question and in this comment) is to create a synonym $\to$ .

It is worth mentioning that many people use the term topology in wider sense, including general topology, algebraic topology, differential topology, etc. (The fact that the tag was used in this way is probably the reason why the tags had previously to be removed manually and not simply by synonymizing the two tags.)

So making a synonym could lead to a danger that some users will use this tag incorrectly. (I.e., not as a synonym of , but using the word topology in the wider, more inclusive, sense.)

Considering this, it might be better not to create the synonym and try to think of other possible solutions instead.

You can use upvotes/downvotes on this post to show whether you agree with this assessment.


It might be worth mentioning that on math.SE there is was a synonym topology $\to$ general-topology for a long time, it was later removed. However, it might be rather difficult to find out whether the synonym has caused some questions to be incorrectly tagged.

But the situation on these two sites is somewhat different. On math.SE, (general-topology) is by far the largest from the topology-related tags. (Which is not surprising, considering that elementary questions are more often asked on MSE than on MO.) On Mathoverflow, the biggest topology-related tag is with above 4k questions at the moment. Both and are somewhere around 2k.

  • 3
    $\begingroup$ For the three most recent instances, it seems to me that "general topology" was an acceptable replacement. Off-hand, my feeling is that there's not much of a danger: in the (probably) rare cases where "general topology" was a misnomer, the tag could be edited on an ad hoc basis. $\endgroup$
    – Todd Trimble Mod
    Commented Jun 24, 2016 at 11:51
  • $\begingroup$ Related discussion in chat: chat.stackexchange.com/rooms/10243/conversation/… $\endgroup$ Commented Jul 2, 2016 at 10:47
  • 1
    $\begingroup$ Martin, I had read the discussion you and quid were having. I am fine with the idea of just killing off the tag if and when it appears. $\endgroup$
    – Todd Trimble Mod
    Commented Jul 2, 2016 at 11:30
  • $\begingroup$ As mentioned by François G. Dorais in chat, there is currently a synonym (topology) $\to$ (gn.general-topology). Based on his comment, it seems to be a test to see whether this will lead to some incorrectly tagged questions or not. $\endgroup$ Commented Nov 21, 2017 at 9:45

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