Digging in the SEDE, I've found 3 question pairs being each other's dupe. Namely:

  1. this and this,
  2. this and this,
  3. and this and this.

Today we can't close a question as a dupe, if it would create such a dupe circle. But it is a new development in the software, and it did not affect the already existing circles.

In order to make the question catalog more consistent, I would suggest to do something with them:

  • Vote the better to reopen (note: chronological order doesn't matter, nothing forbids a question to be a dupe of a later posted one).
  • Vote to delete one of them (note: keep the relevant rules, particularly avoiding the deletion of good answers).
  • If some exceptional circumstance would require it, then flag for mod intervention (merge suggestions, or dealing with multiple originals).
  • 5
    $\begingroup$ Somewhat related: What should I do when I find circularity among duplicates? $\endgroup$ Sep 5, 2019 at 17:48
  • $\begingroup$ top two pairs have user Micah on both. last pair has @hardmath on both. $\endgroup$
    – user645636
    Sep 5, 2019 at 21:57
  • 1
    $\begingroup$ @GerryMyerson Only the link in this meta post was wrong, the question is still a part of a mutual dupe pair. I fixed the link. $\endgroup$
    – peterh
    Sep 6, 2019 at 10:12
  • $\begingroup$ What I see quite shocking, that not even a single reopen vote arrived to any of the questions. $\endgroup$
    – peterh
    Sep 6, 2019 at 11:06
  • $\begingroup$ even with the fix, there's actually two users that voted duplicate for both questions in the 3rd pair. $\endgroup$
    – user645636
    Sep 6, 2019 at 12:14
  • $\begingroup$ @RoddyMacPhee Not 2, but 10. Closure by community vote requires 5 close votes per question. $\endgroup$
    – peterh
    Sep 6, 2019 at 12:17
  • $\begingroup$ I mean that if you look at the 10 people in the last pair there are two from each set of 5 that are the same. $\endgroup$
    – user645636
    Sep 6, 2019 at 12:21
  • 2
    $\begingroup$ Quite frankly why is the lack of instant votes shocking? I mean in my book it's pretty sensible not to jump onto that and muddy the waters of the context of the question via distorting the very thing it asks about. I mean the situation persists since a long time, maybe a couple more days are not the end of the world. $\endgroup$
    – quid Mod
    Sep 6, 2019 at 19:10
  • 1
    $\begingroup$ @quid Well, it is right. I've just tought, that the nearly democratic community mechanisms will quickly handle the situation - everybody votes as he thinks the best option, and then the rules will decide, what will happen. What I find... surprising, that not a single for me visible vote was cast. Another option had been to flag the questions, maybe I should have done this. $\endgroup$
    – peterh
    Sep 6, 2019 at 19:41
  • 1
    $\begingroup$ @quid Maybe we could interpret it also as that the community finds the situation interesting (post score), but has no problem with the dupe circles (no votes cast). $\endgroup$
    – peterh
    Sep 6, 2019 at 19:43
  • 1
    $\begingroup$ @quid Btw, I think if you (mods) would solve the problem (reopen/merge/delete), I think, despite the lack of the community activity to solve the problem, no one will say "bad mods, I want the dupe circles back". Thus, another possible interpretation of the result is that the community abstains to say, what to do. Thus, nothing forbids the mod intervention to handle these exceptional main site question relations. $\endgroup$
    – peterh
    Sep 7, 2019 at 22:08
  • $\begingroup$ One never knows! I think we should better post a poll, so that we know for sure. ;-) More seriously, I'll look into it. The week was a bit busy for me, and it seems also for other mods, thus it was not really addressed. $\endgroup$
    – quid Mod
    Sep 7, 2019 at 22:13

1 Answer 1


For the first pair of links, I think merging would be useful. The second question contains more context, and also has a nice approach by @user1337 that is different from the rest of the answers in both links. So, I suggest reopening the second question and merging the first question with the second.

For the second pair of links, I think it would be alright to delete the second question, since both the answers are just hints to look at the Jordan canonical form. On the other hand, the first question has (in my opinion) a useful incorrect attempt by the OP, which is addressed in the answers while the main question is also answered. So, I suggest reopening the first question and deleting the second.

For the third pair of links, I think merging would be useful. They are both literally the same question, posted by the same OP. The OP also responded to Jyrki's comment under the later question as to why the same question was reposted. I suggest that we reopen the later question and merge the older one with it.

  • $\begingroup$ I've cast reopen votes on the two Questions you suggested. Note however that one of these (second Q of first pair) was additionally identified as duplicate of another Q not involved in the circularity of references. $\endgroup$
    – hardmath
    Sep 8, 2019 at 5:08
  • $\begingroup$ I treated 2 and 3 as proposed. For 1, I removed one of the dupe targets in the one post thus breaking the circle. I have no strong opinion if the one should be reopened or not. Actually I also merged (despite the factor of 2.) $\endgroup$
    – quid Mod
    Sep 8, 2019 at 21:09

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