I asked the question

"Which sets occur as boundaries of other sets in topological spaces?"

on MathStackExchange on June 23, thinking that the answer is probably known, but there are no answers yet. Is this sufficient reason to ask it again on Mathoverflow? Am I likely to get answers then?

  • $\begingroup$ It seems you got an answer. Now, you might not be satisfied with the answer, but this can also mean that the questions was not quite clear. $\endgroup$ – user9072 Jul 9 '14 at 8:54
  • $\begingroup$ @quid No, there are no answers yet, only a comment (and some other deleted comments, now integrated into the question). $\endgroup$ – N Unnikrishnan Jul 9 '14 at 11:06
  • $\begingroup$ I meant the partial answer given in a comment. $\endgroup$ – user9072 Jul 9 '14 at 12:28
  • $\begingroup$ Seems like this meta question has provoked another helpful comment - maybe not necessary. $\endgroup$ – user25199 Jul 9 '14 at 12:33
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    $\begingroup$ Why was this downvoted? Irrespective of whether it’s appropriate to move the question to MO, it is appropriate and on-topic to inquire about it here on meta. $\endgroup$ – Emil Jeřábek Jul 9 '14 at 19:20
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    $\begingroup$ The comment I made on MSO implies that spaces with the required property must be perfect. I think one can show that this is also sufficient for $T_0$ second-countable spaces (that is, if $X$ is $T_0$ second-countable, then every closed subset of $X'$ is a boundary of a subset of $X$, even one with an empty interior). However, it seems to me that the question may be rather nontrivial in full generality, and that it is fine to re-ask it on MO. $\endgroup$ – Emil Jeřábek Jul 9 '14 at 21:43
  • $\begingroup$ @Emil Good point. I agree the question looks fine for MO, preferably with a link here. $\endgroup$ – user25199 Jul 10 '14 at 10:27
  • $\begingroup$ I think that @EmilJeřábek comment shows that a revised version of the question would be fine. Why not instead of migrating it ask a question taking the information obtained via comment(answers) into account, linking to oiriginal and the meta question. Or if you really want to migrate it, edit it beforehand. $\endgroup$ – user9072 Jul 10 '14 at 17:23
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    $\begingroup$ @quid, EmilJerabek, Carl Thanks for the responses, I am reposting it here on MO. $\endgroup$ – N Unnikrishnan Jul 10 '14 at 20:31
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    $\begingroup$ @quid By the way, by migrating I have always meant just copying the post manually and reposting, with revisions. Is there another way of making that happen? $\endgroup$ – N Unnikrishnan Jul 10 '14 at 20:33
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    $\begingroup$ Yes. In fact "migration" is a particular technical term in the Stack Exchange network. See meta.stackexchange.com/questions/10249/… $\endgroup$ – user9072 Jul 10 '14 at 22:05

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