Before the question Intuitive explanation of concentration of the measure for spheres has been marked as duplicate (correctly I believe), it has got an answer which might provide additional useful information. When viewing the question whose duplicate it is there is no way to know about it.

There seems to be some discussion on meta related to this in Closing as duplicate, but it seems that nothing definite has come out of it.

In fact also more generally there might be cases when there is something useful in answers to closed questions although I cannot think of any other specific examples.

Do you agree there is a problem here? If not, why? If yes, do you have a proposal for it? I cannot think of any satisfactory solution but I think something must be done about it.

Update: I now have an example of that different kind, - a question closed as off-topic (maybe rightly so) with a really beautiful answer: Are there any rational solutions to this octic equation? - a clear instance of the already widely discussed stone soup, though

  • $\begingroup$ I’d say, encourage the author of the answer to repost it under the non-closed question, or failing that, link from that question back to the duplicate in a comment. $\endgroup$ Commented Aug 24, 2016 at 11:43
  • 2
    $\begingroup$ In some cases questions can be merged. (If the notation and terminology in both duplicate questions is such that the answer makes sense as an answer to the duplicate target without any changes.) If this is the case, you can simply flag the question and ask the moderators to merge the two questions. $\endgroup$ Commented Aug 25, 2016 at 5:35
  • 3
    $\begingroup$ Re: There is no way to know about it. All duplicates are listed as linked questions in the sidebar. And, if some of the answers to the duplicate is worth pointing out, make a comment adding a direct link and explaining what information it adds. $\endgroup$ Commented Aug 25, 2016 at 5:37
  • $\begingroup$ @MartinSleziak Thanks for the information! And sorry for the second one, should notice it myself. Could you turn your comments into an answer? I think it is still useful to keep this question - if anything, for the absent-minded, like me. $\endgroup$ Commented Aug 25, 2016 at 6:06
  • 2
    $\begingroup$ This post on meta.SE also gives some advice on this: How can awesome answers to average or duplicate questions be promoted? $\endgroup$ Commented Sep 2, 2016 at 7:37
  • 1
    $\begingroup$ Related: meta.mathoverflow.net/questions/1046/…. Though this relates not so much to duplicates as to "some other reason". $\endgroup$ Commented Sep 6, 2016 at 19:43
  • 2
    $\begingroup$ A closed question and its answers can still be viewed and referenced. But we need to do something to prevent over-eager deleters from getting at it! $\endgroup$ Commented Oct 8, 2016 at 13:47

1 Answer 1


Per the OP's request I am posting information from the above comments as an answer. (Although personally I think that this addresses the OP's concerns only partially.)

In some cases questions can be merged. Merging is possible when the notation and terminology in both questions are identical, or at least similar enough that the answer still makes sense even after being moved to the other question. If you think that some pair of questions can be merged, you can flag the question and ask moderators to merge them.

Another point raised by the OP is that "There is no way to know about it." (I.e., knowing about the duplicate questions which might contain additional information.) All duplicates are listed as linked questions in the sidebar. And, if some of the answers to the duplicate is worth pointing out, make a comment adding a direct link and explaining what information it adds. (I believe that in general when you find a question which is of interest to you, checking both the comments and the linked and related posts is a reasonable thing to do.)

EDIT: Later I found this post on meta.SE: How can awesome answers to average or duplicate questions be promoted? It deals with a similar issue as this question. As you can see, one of the answers mentions merging as the possibility. (But I will repeat again that merging is only possible if the answer to the closed question also works as answer to the duplicate question.)

  • $\begingroup$ Comments are not meant to be important. They shouldn't contain relevant information. $\endgroup$
    – Polygnome
    Commented Aug 25, 2016 at 8:38
  • 7
    $\begingroup$ @Polygnome Whether it is good or bad, my whole experience with MO shows that comments are extremely important here $\endgroup$ Commented Aug 26, 2016 at 19:09
  • $\begingroup$ Thats not how SE is meant to work. If that is the case, then the community should really start thinking about trying to shift this. SE is meant to be a Q&A, information should be contained inside the answer. if there is relevant information missing, the answerer should include, or the commenter instead provide his own answer or edit the existing answers. there are meta discussions about that policy for the whole Se to be found both at meta SO and meta SE. not obeying the SE standards will only lead to problems in the long run, especially with he way the software treats comments. $\endgroup$
    – Polygnome
    Commented Aug 26, 2016 at 19:13
  • 9
    $\begingroup$ @Polygnome, you will find when you explore various parts of StackExchange that the parts use the platform differently. MathOverflow has been an established and successful forum, enough so that considerations were made to preserve the culture and many of the ways that the community used the forum. Your statement in your first comment is challenged by over six years of community experience. I recommend that you do more research before making statements about how things are supposed to work. Gerhard "Signatures Serve A Purpose Too" Paseman, 2016.08.26. $\endgroup$ Commented Aug 26, 2016 at 19:27
  • $\begingroup$ @Polygnome As I can see, in a situation when you want to add a link to another question which is relevant for the OP for some reason, you use comments. That's along the lines of my suggestion. $\endgroup$ Commented Aug 26, 2016 at 19:43
  • $\begingroup$ @MartinSleziak The question was going to be closed as it was completely off-topic. There was neither a place for an answer nor would one have been appropriate. The comment is not intended to be lasting information for future users, but I nonetheless wanted to give the OP - and only the OP - a starting point where he can look. That is completely different from leaving relevant information that is important for future users. But kudos that you made the effort to go through my comments just to make your point ;) $\endgroup$
    – Polygnome
    Commented Aug 26, 2016 at 19:46
  • $\begingroup$ @Polygnome I only had to look at your 5 last comments to find this one, so it seems very likely that there are some other comments like that. But I think that's not the point here. I offered the best advice to the situation described by the OP I was able to think of. I hope that somebody can come up with a better suggestion and posts it as an answer. $\endgroup$ Commented Aug 26, 2016 at 19:49
  • $\begingroup$ @GerhardPaseman I am active on various SE sites. But some policies are set directly on Meta Se and are simply valid through the fact that all SE sites use the same basic principles. But the fact that Q&A are the core concept of SE and comments are not supposed to contain relevant information that should be a part of the answer is a core concept of the whole SE. If you decide to ignore that, fine, but its really not the best way to go about it. It gets probems, because the devs develop the SE platform with things in mind that work for all platforms, and so might screw with comments as well. $\endgroup$
    – Polygnome
    Commented Aug 26, 2016 at 19:50
  • 6
    $\begingroup$ @Polygnome In a sense, you contradict yourself :P In your comments, you are providing important information - you express your opinion on a highly relevant matter and support this opinion with quite essential arguments. Where else would you find it appropriate to do all this? :D $\endgroup$ Commented Aug 30, 2016 at 9:40
  • 5
    $\begingroup$ @Polygnome You should bear in mind that MO has a special status within the SE network, even if you take the (extreme) stance that SE standards automatically overrule site policies. Not only is MO still not fully integrated into the network software, but it has special dispensation to Do Things Differently Here (TM) -- this was in fact one of the conditions for MO to join the SE network. $\endgroup$ Commented Sep 2, 2016 at 11:35
  • 1
    $\begingroup$ @ChristianClason Thats interesting... is there some resouce to read about the history of MO? Since most things at least work somewhat similar on all SE sites. $\endgroup$
    – Polygnome
    Commented Sep 2, 2016 at 11:42
  • 2
    $\begingroup$ @Polygnome A lot is documented in the discussions leading up to and shortly after the joining on Meta (after) and its precursor tea.mathoverflow.net (before). A short overview is meta.mathoverflow.net/questions/753/history-of-mathoverflow. $\endgroup$ Commented Sep 2, 2016 at 11:47
  • 5
    $\begingroup$ @Polygnome Some links related to that: Mathoverflow - why so different (at Meta.SE), History of MathOverflow. There are also some discussions about migration on tea (=meta.MO before the migration) like this one. IIRC there was some legal agreement between MO and SE, I was not able to find exact text. I vaguely recall that it mentioned even a possibility of MO to get out from the SE network again. (Although I consider that possibility unlikely.) $\endgroup$ Commented Sep 2, 2016 at 11:54
  • 3
    $\begingroup$ @Polygnom I found the agreement between MO and SE. It was mentioned in this answer and the link is here. $\endgroup$ Commented Sep 3, 2016 at 18:52

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .