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$\begingroup$

The purpose of this thread is to help focus the attention of the community on posts that may require exceptional handling. This includes requests for reopen and undeletion votes. A request should be posted as an answer below.

Please do not use this thread to engage in debates on contentious matters (e.g. reasons for closure). That should be done in a separate linked thread. The goal is to keep this meta thread free of tension, so that everyone feels comfortable posting here. Please be polite, and respect the many different viewpoints in our diverse community.

To inform readers of the current (and past) states of the targeted post, please append tags such [REOPENED,RECLOSED] or [UNDELETED] at the start of the answer.

Beware that "short" requests such as "request reopening of <link>" may be automatically converted to comments by the SE software, so you may need to write more (e.g. why you think that the question should be reopened or undeleted).

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  • $\begingroup$ For reopen requests that are run-of-the-mill (e.g. aren't meant to debate reasons for closure), do you think it would make sense to have a generic reopen-request thread, so that we don't end up with hundreds or thousands of questions on such. Then each request would simply be an answer in the reopen thread, and it being bumped would get the same exposure as a new question. Thoughts? Unless I hear any objections I will create such a thread. $\endgroup$
    – Bill Dubuque
    Commented Oct 24, 2012 at 17:11
  • $\begingroup$ @Bill: Yes. This crossed my mind after posting this. I agree that it would be a good idea. $\endgroup$
    – Asaf Karagila Mod
    Commented Oct 24, 2012 at 17:37
  • $\begingroup$ I didn't expect that you would edit this specific question into the general question (I was writing another). But since it is done, we may as well go with it. $\endgroup$
    – Bill Dubuque
    Commented Oct 24, 2012 at 18:28
  • 3
    $\begingroup$ @Bill: I saw no reason to wait with that idea. There was no actual discussion in this thread anyway. $\endgroup$
    – Asaf Karagila Mod
    Commented Oct 24, 2012 at 18:34
  • 2
    $\begingroup$ @Gerry: The solution would be to add a few words, I suppose. For example why it should be reopened. $\endgroup$
    – Asaf Karagila Mod
    Commented Nov 9, 2012 at 12:16
  • 3
    $\begingroup$ @Asaf, I opted for cursing the darkness rather than lighting a candle. Anyway, the question has been reopened. $\endgroup$
    – Gerry Myerson
    Commented Nov 9, 2012 at 21:54
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    $\begingroup$ @Gerry: Darkness is just the light's way of proving the empty set exists. $\endgroup$
    – Asaf Karagila Mod
    Commented Nov 9, 2012 at 21:55
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    $\begingroup$ @Willie: I think that we should delete old reopening requests and perhaps have one post/additional thread for indexing them. I should also think that any request older than $n$ days for some reasonable $n$ should be deleted. If something has not been reopened and the initial votes expired... well, it makes sense to conclude that there aren't that many people interested in reopening. $\endgroup$
    – Asaf Karagila Mod
    Commented Nov 30, 2012 at 9:49
  • 4
    $\begingroup$ @Willie It's probably useful to have some nontrivial history remain so that folks $\rm < 10K$ can gain some idea about what types of questions do get reopened, and what types don't. By quickly scanning the requests it might help to convey some idea of the community consensus on marginal topics. To keep the unopened requests at the top of the active sort, they could easily be bumped if there is still interest. $\endgroup$
    – Bill Dubuque
    Commented Dec 1, 2012 at 1:44
  • 5
    $\begingroup$ @Belgi: This is why I prefer to browse Meta with answers sorted by activity. $\endgroup$
    – user856
    Commented Jan 5, 2013 at 21:38
  • 4
    $\begingroup$ @Belgi Sorting by activity solves the problem. I just bumped the only active discussion to the top with an edit. There are two requests dated by November 2012, which I guess are no longer ongoing conversations (but anyone so inclined can bump them; it's a CW). $\endgroup$
    – user53153
    Commented Jan 5, 2013 at 22:07
  • 1
    $\begingroup$ Thanks for the workaround, I still think theres no reasons for this to log all reopen request that were/will be made $\endgroup$
    – Belgi
    Commented Jan 5, 2013 at 22:10
  • 5
    $\begingroup$ Per the (short) discussion in this deleted meta post, I have edited this thread to support requests for votes to undelete as well as votes to reopen. $\endgroup$
    – Alexander Gruber Mod
    Commented Jul 13, 2014 at 14:59
  • 1
    $\begingroup$ The question got protected again; I'd assume, but cannot check, since it fulfills criteria for autoprotection The simplest way out would be to restart a question of this form. IMO this would be desirable regardless the protection issue. $\endgroup$
    – quid
    Commented Oct 17, 2014 at 13:58
  • 2
    $\begingroup$ @quid: Yes, yes, I see that protection triggering every time I remove it. But I gave it some more thought, and for now it seems harmless after all. $\endgroup$
    – Asaf Karagila Mod
    Commented Oct 17, 2014 at 14:06

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This question: How come $1^{\infty}$ = undefined, while $2^{\infty} = \infty$ and $0^{\infty} = 0$? was closed as a duplicate of Why is $1^{\infty}$ considered to be an indeterminate form. I know that this is a tight one, but I do think that they are different in that one question asks why $1^{\infty}$ is an indeterminant form. The other asks shy $1^{\infty}$ is undefined. I think that this is slightly different so I request that the question be reopened.

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[REOPENED]

I'm not sure why this question was put on hold for being "not about mathematics". There seems to be an answerable question there (with a tentative answer of "yes, in a sense") with some leads by olive euler and Semiclassical in the comments.

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[REOPENED]

Finding $\int_0^{\frac{\pi}{2}}\arctan\left(\sin x\right)dx$ was closed as a duplicate of Evaluating a sum involving binomial coefficient in denominator. While the statement of the closed question is mentioned in a later edit to the supposed original, the path leading from the integral to the sum is not part of the supposed original question.

Only half of the closed question is answered in the supposed original question. Therefore, I think that the question should be reopened.

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  • $\begingroup$ It has 4 reopen votes, so you can cast one without using moderator powers. $\endgroup$
    – Jonas Meyer
    Commented Dec 6, 2014 at 16:47
  • $\begingroup$ @JonasMeyer: thanks. Done. $\endgroup$
    – robjohn Mod
    Commented Dec 6, 2014 at 17:05
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[REOPENED. I cast the binding fourth vote on behalf of myself and Bill Dubuque]

This question: Prove $f(S \cap T) \subseteq f(S) \cap f(T)$ was voted to be closed as a duplicate of Is this a valid proof of $f(S \cap T) \subseteq f(S) \cap f(T)$?

However, the question asked actually was different. The latter asks for the readers to check whether the OP gave a valid proof (he didn't, and counterexamples were given as answers). The former asks for a proof. The closest answer we have on the latter to this question is this sketch of a proof. So I don't really think the two are exact duplicates of each other.

(The other proposed duplicate target is a mistake, as noted in the comments.)

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    $\begingroup$ I agree, since your vote and mine bring the count to 5, you should feel welcome to reopen it. $\endgroup$
    – Bill Dubuque
    Commented Nov 6, 2012 at 14:33
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[REOPENED] I would like the following: is $0.\overline{99}$ the same as $\lim_{x \to 1} x$?

to be reopened. The question is currently closed as a duplicate of Is it true that $0.999999999\ldots = 1$?.

While I agree that at the base is indeed that $0.\overline{9}$ = 1, but the OP actually says that he/she knows the proof of this. It seems like the question is more about the confusion about the function that is introduced in the question. While the question might not be worded perfectly, I don't think that it should be closed.

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[REOPENED]The question A question about series with a strange property. should be re-opened. As the OP remarked the supposed duplicate does not actually answer the question posed.

(More details: the supposed duplicate has two questions in it. One without sign restrictions. The other restricting to positive series. An answer was given and accepted for the latter. But no answer was given for the former. The new question explicitly asks for the former.)

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[REOPENED] This question about a set containing itself was closed as "not a real question", with both posted answers interpreting it as a tautology that $X \subseteq X$. However, the question is really about the paradox $X \in X$; the word contains can have another meaning as $\ni$, and the question actually mentions the axiom of regularity! Granted, it's not a great question, and is easily resolved by prodding the asker about the definition of set complement, but that doesn't make it "not a real question".

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[REOPENED] I would like to see this post reopened.

It is clear that it generated a lot of thought about relations, their properties, etc. Many questions of this nature are posted to this site, and are not closed as "non-constructive." Many students are very interested in "real-life" applications/interpretations of the math they are learning. ${}$

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    $\begingroup$ I don't think this post should be re-opened, although I agree that "non-constructive" might be off-putting. I think that the question generated a lot of buzz, which is good, but when you have several repeated answers and deletions it's time to close down. If we had "no longer relevant" as a closing reason I would vote that. $\endgroup$
    – Asaf Karagila Mod
    Commented Jan 5, 2013 at 14:09
  • $\begingroup$ @Asaf I'd suggest protecting the question, if reopened. I do understand your point, and I think if the closure reason could be customized by a moderator to indicate what you suggest, I'd be okay with that. $\endgroup$
    – amWhy
    Commented Jan 5, 2013 at 14:12
  • $\begingroup$ I agree and have also voted to reopen. I think protecting the question is more appropriate. $\endgroup$
    – TMM
    Commented Jan 5, 2013 at 19:31
  • $\begingroup$ I have to say that I also agree with Asaf. "non-constructive" portrays an inaccurate perspective on what is being meant; it is clear that the question is simply no longer relevant. Although, there's a possibility that a user could input a very interesting answer and I am not entirely sure why this should not occur. I do not fully understand the things between the lines of the FAQ and rules of the site, though! I have not voted to reopen as I do not fully comprehend the critique of those who voted to close and I'd rather not step on any toes. $\endgroup$
    – 000
    Commented Jan 5, 2013 at 19:42
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[REOPENED] Please reopen From a mathematician's point of view, what is the purpose of '$dx$' in $\int f(x)\ dx$?. I had written out (what I thought of as) a nice answer, then just before trying to post it, it was closed as a duplicate of What is $dx$ in integration?.

However, this question is different since it deals with the difference in the way physicists and mathematicians understand $dx$ (something that my answer was going to address).

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[REOPENED] In this question, the OP has edited to point out why the question isn't a duplicate. Please reopen.

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[REOPENED] I would like to see How to prove the earning decomposition of 2 people in mediocristan and extremistan? reopened. Please note that a highly reputed user has added a comment saying: "I would like to reopen and answer."

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[REOPENED]

The question Probability of random integer's digits summing to 12 was recently closed despite several well-supported requests in the comments that it not be closed (two of the close votes came after these comments were posted) and despite that it was a legitimate question, well-posed, clear, and attracted several constructive answers.

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[REOPENED] This question was closed as a duplicate (by a single binding moderator vote). However, the question is certainly not a duplicate of the linked question, since the author is asking additionally a more general question, namely "What are those number theoretic situations?" (where the unit group is cyclic). This is an interesting question that is not addressed at all in the proposed duplicate.

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[REOPENED] [This question]1 was closed as a duplicate. It's not a duplicate for two reasons. The major reason is that the question was not about how to solve the problem but about where the OP's own calculations went wrong. The minor reason is that the other question is more general and the generality requires more complicated answers that make it more difficult to find the error in the present simpler calculations. Please reopen.

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[REOPENED] (Thanks. That was fast!)

This question was closed, I just found out, because it came as part of a contest, whose deadline has passed. Now that the deadline is behind us, I think it deserves to be reopened, and it may receive interesting answers.

There is also a nice answer that was deleted for this reason, and I believe it should be undeleted as well.

(Related to this: It would be nice if, in case this happens again, all people who posted answers are notified. As I said, I just noticed today, by coincidence, that the question was part of a contest, was closed, and an answer was deleted. A comment informing me would have been appreciated. I imagine other people in similar situations would appreciate such courtesy as well.)

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[REOPENED] (Tons of thanks!)

My question "How to show the relation $<$ is not definable in $(\Bbb N; 0, \operatorname {S})$ by quantifier elimination?" is closed as duplicate.

The fault is on my side, since I weren't aware of the two duplicate questions on this site and failed to add the link to stress the difference between my difficulty and the former OP's. In particular,the thing I want to know is how to show that by quantifier elimination, while the existing answers are both using automorphism.

Now I have edited the question accordingly. Could you please vote to reopen the question?

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[REOPENED] I voted to close Books to understand the construction of all groups of a specific order because the OP originally gave a confused presentation. However @JackSchmidt has provided a nicely reworded version, and I have voted to reopen.

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[REOPENED] This question was closed, (I suspect) because it had unprocessed TeX. The question was improved afterwards, and does not deserve to be closed anymore.

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[REOPENED] I would like to see this question re-opened. I believe it was closed because the OP was asking a question which showed a fundamental miss-understanding. Such a question should receive attention, and the OP should be helped. Closing it is, well, pointless.

(Also, if you dig into the closing, you will see that it is closed not because it has five votes to close but because a moderator cast the fourth vote and a moderator's vote is binding (the question is closed immediately). According to the Review, there were three votes to leave open, two to close.)

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  • $\begingroup$ Could the down-voter please tell me their thoughts? I am interested in what you think! Make me change my opinion... $\endgroup$
    – user1729
    Commented Jul 1, 2013 at 12:16
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[Re-opened]

This meta question was closed even after the following comment by anorton:

@Closevoters: This is not a duplicate of the suggested duplicate.. That question is talking about a moderator's action, this one is talking about a normal user's action.

which hits the nail on the head.

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[Re-opened]

Generalizations of fitting subgroup was closed because it was incredibly unclear what was being asked. The original poster clarified the question and it is now clear what is being asked.

I am composing a little essay with references on them as I've been studying generalizations of Fitting subgroups for a while now.

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  • $\begingroup$ I disagree that it was incredibly unclear. It was only unclear because noone here had come across the notation before (as is, of course, the way with notation). Although it would have been helpful if he had responded to your comment earlier! Anyway, moot point, and your answer is excellent so +1. $\endgroup$
    – user1729
    Commented Jul 11, 2013 at 8:00
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[REOPENED] This question was put on hold as unclear. It seems perfectly clear to me, and I’ve just given an answer in the comments.

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  • $\begingroup$ The answer you gave seems however incorrect. (See main for details.) $\endgroup$
    – quid
    Commented Jul 29, 2013 at 0:20
  • $\begingroup$ @quid: It is entirely correct. You’ve misunderstood the question. $\endgroup$
    – Brian M. Scott
    Commented Jul 29, 2013 at 0:20
  • $\begingroup$ Sorry for commenting here too (likely I should only have written one comment initially), but now I feel the need to clarify also here that the problem was not me misunderstanding the question. More pertinent to the meta discussion, I might however add that the problem indeed seems understandable as written. Whether or not it is up to the standards of this site is unknown to me (not being very familiar with them). $\endgroup$
    – quid
    Commented Jul 29, 2013 at 7:24
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[Now deleted]

I would like to see this big-list question re-opened. It is on the "Real-world applications of the Fibonacci Series". As I said in the comments, I do not think that this question should be closed. There is a [big-list] tag for a reason. The tag's wiki says "Please do not ask too many of these" not "Do not ever ask these".

Also, I believe that wondering about the applications of different aspects of mathematics is a worthwhile thing to do! If you ever have to write a fellowship application, then it is doubly worthwhile! However, the comments seem to be saying "How dare you ask about applications of mathematics! We do not care about such trifles here!"

I would be grateful if those who want to keep the question closed could comment here on why they have this opinion. You have heard my view, and I am interested in hearing yours.

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    $\begingroup$ @Downvoter: When I wrote "I would be grateful if those who want to keep the question closed could comment here on why they have this opinion", I was talking to you... $\endgroup$
    – user1729
    Commented Jul 17, 2013 at 12:15
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    $\begingroup$ Sorry I just saw this. I think the question should remain closed until the OP has suitably narrowed the question down (or split in to distinct posts) to something which can be answered in a few paragraphs. As it stands, there are two 'big list' questions only tangentially related to each other, and another question which could receive some great attention as a history of maths questions if posted separately. I've added a comment to the same affect on the question. $\endgroup$
    – Dan Rust
    Commented Jul 24, 2013 at 12:59
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[Re-closed as duplicate about Cartesian to Polar change of variables. See comment below.]

I propose that we should reopen this question question, and posted my reason in the comments.

It was closed as an exact duplicate of a thread asking how to evaluate a Gaussian integral. But actually, the question was why, when one converts from Cartesian to polar coordinates, $dx\,dy$ gets replaced by $r\,dr\,d\theta$. That's not what the other question was about. There are other ways to evaluate the Gaussian integral than by polar coordinates, and those other ways would be appropriate answers to that older question, but not to this one. In some ways, the presence of a Gaussian integral in this question is incidental. It was really only the particular occasion for the question about polar coordinates.

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[REOPENED]

I'd like to see this question reopened. Initially, the OP was attempting to prove the (false) statement that an infinite Hausdorff space has infinitely-many isolated points, but altered the question after this was pointed out. It now asks the much more interesting question as to whether every Hausdorff space has an infinite subspace, all of whose points are isolated, based on the example of $\Bbb N$ in $\Bbb R$.

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  • $\begingroup$ But the new version still has a trivial counterexample. $\endgroup$
    – Tobias Kildetoft
    Commented Oct 26, 2013 at 18:06
  • $\begingroup$ I have fixed it (if I correctly figured out what you meant). $\endgroup$
    – Cameron Buie
    Commented Oct 26, 2013 at 18:14
  • $\begingroup$ However, if there is still a (trivial) counterexample, @Tobias, please post it as an answer, and resolve the issue completely and finally. $\endgroup$
    – Cameron Buie
    Commented Oct 27, 2013 at 13:35
  • $\begingroup$ I only meant the finite one. I have not thought further about the infinite one (but since no example pops to mind, I find that it is probably a worthwhile question, even if a trivial counterexample turns out to exist). $\endgroup$
    – Tobias Kildetoft
    Commented Oct 28, 2013 at 7:19
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[REOPENED]

I would like this question reopened. Closing it because the OP didn't state anything beyond the bare question is a little harsh, and the question is interesting.

EDIT: Paul Siegel's answer has been accepted with 3 upvotes. That seems to indicate that reopening is appropriate.

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  • $\begingroup$ Why not wait that the OP "add(s) in what (they) have tried and where (they) came across", as was suggested to the OP in a detailed comment? $\endgroup$
    – Did
    Commented Nov 3, 2013 at 21:40
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    $\begingroup$ @Did: because closing it seems like a heavy-handed way to get the OP to respond. The detailed comment that was left was more than sufficient. $\endgroup$
    – Cheerful Parsnip
    Commented Nov 3, 2013 at 22:22
  • $\begingroup$ The problem is indeed interesting, and currently has a solution that could use checking (I fixed some of the problems, I think, but I don't know if I did so correctly). I don't know, however, about the bad precedent that could set.... $\endgroup$
    – dfeuer
    Commented Nov 5, 2013 at 2:02
  • $\begingroup$ @dfeuer: There are plenty of questions where the OP only states the problem which have not been closed. Closing this questions strikes me as absurdly harsh. $\endgroup$
    – Cheerful Parsnip
    Commented Nov 5, 2013 at 2:27
  • $\begingroup$ Of course the best turn of events would be if the OP edits. $\endgroup$
    – Cheerful Parsnip
    Commented Nov 5, 2013 at 2:28
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    $\begingroup$ @GrumpyParsnip Two weeks later... and in view of the subsequent (or lack of) events, do you still hold the same view? $\endgroup$
    – Did
    Commented Nov 17, 2013 at 14:47
  • $\begingroup$ @Did: maybe a good course of action would be to reopen - and wiki-fy - the question. Then the OP doesn't get any reputation (and the thought that they did anything right...), but the community still gets the benefit of having answers to the question. Granted, there are already answers... $\endgroup$
    – The Chaz 2.0
    Commented Nov 17, 2013 at 15:10
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    $\begingroup$ @Did: I still think it deserves to be reopened, even if it has been abandoned by the OP. It's the question itself that is interesting, not the person behind it. $\endgroup$
    – Cheerful Parsnip
    Commented Nov 17, 2013 at 19:52
  • $\begingroup$ It's really not clear to me how one goes about drawing enough attention to reopen. $\endgroup$
    – dfeuer
    Commented Nov 26, 2013 at 16:50
  • $\begingroup$ @dfeuer: I edited the answer to bump it to the forefront. $\endgroup$
    – Cheerful Parsnip
    Commented Nov 26, 2013 at 17:23
  • $\begingroup$ @dfeuer: thanks for fixing my comment. $\endgroup$
    – Cheerful Parsnip
    Commented Nov 26, 2013 at 19:17
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[REOPENED]

This question is typical basic linear algebra homework, directly pasted from the textbook. So it sure looks bad at first.

But read until the end... the OP actually proposed answers for every question and is simply asking for confirmation. So s/he probably did not get that from an answer key.

This certainly includes the OP's attempts to solve the problem, and I don't understand why it was closed. At least not for the specific reason which is mentioned. What is unclear here for sure is the message sent to the OP...

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[REOPENED] Thanks.

This question has been put on hold as off-topic. I would like to see this reopened because:

1 - Unless I missed something, this is not exactly an easy question. If it is, anyway, I would really like to see easier solutions. This was not a routine reasoning for me, so if I made mistakes, I would really like interested people to point them out.

2 - For sure, it is a natural one for which the context had been provided by the OP: s/he mentioned Carleman's and Hardy's inequality, and this is the $p=-1$ case of the latter which is known to hold for $p>1$ when you read the wikipedia entry, for instance.

3 - Although I expect an OP to share some thoughts/efforts, on a trivial/standard question, I don't care if the OP does not add "I tried this (whatever) and it did not work, can you help me please?" on a harder question.

4 - This is the question I've been the most interested in for quite some time. I did not even know about Carleman's and Hardy's inequality: so I've learned something and I have had a lot of fun looking for the answers. Exactly what I am here for.

5 - I would enjoy seeing other answers with different approaches.

6 - I recall this OP had already asked several interesting nontrivial complex analysis questions from a book s/he was reading. Please let us not shy this user away from asking questions.

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[REOPENED]

The author of this question added the requested details before the last "no context" vote was cast, so the question should be reopened.

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[REOPENED]

This question was closed as a duplicate, but the question specifically asks not for a proof (which the OP knows) but, instead, for some intuition behind successful strategies for constructing such proofs - something that is not addressed at all in the proposed duplicate. Probably there is a good chance of further helpful answers appearing if it is reopened.

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