# Requests for Reopen & Undeletion Votes, etc. (volume 01/2015 - 07/2018 ) [duplicate]

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 prepend tags such as:

Reopened, reclosed or

Undeleted

at the start of the answer when a change of status occurs. (This also makes it easier to browse through the list by creating a visual difference for posts that still require action.)

Beware that "short" requests such as "request reopening of " 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).

Notice that the first edit after the question was put on-hold pushes the question into reopen review queue, if the edit was done withing 5 days of closure. So does a reopen vote. It is reasonable to wait until the review is finished before posting here. (If the review has already been finished, it is shown on the timeline of the question.)

(description copied from the old thread)

As has been proposed in chat (and seconded by a couple of users), it seems that it is time to create a new thread for reopen and undeletion requests. The old thread (as of now) has over $200$ answers, and it is really hard to scroll through the mass of old and/or possibly outdated answers--voting is a mess, too. (It's especially problematic for 10k users who can see the deleted posts.)

Reopened.

Could someone help me with the maths behind this calculator?

This is a good problem which the OP didn't know how to formulate mathematically. I've edited to make clear it is about how best to hedge a particular bet and to frame it as a mathematical problem.

• While you may indeed have created a fairly self-contained math problem, unrecognizable from the OP's formulation, it is still a request for advice about how to gamble. Such requests strike me as have pecuniary motivations rather than educational ones. – hardmath Nov 26 '16 at 22:24
• I disagree about unrecognisable - one look at the page the op linked shows what they're trying to do, and all I did was spell that out, not create anything new. – Matthew Towers Nov 27 '16 at 0:17
• You are referring to the out-of-site page the OP linked to while @hardmath is mentioning the actual text of the question (on this site). That you have to refer to some other content than the question itself to motivate it goes towards closure (remember that questions should be self contained). – Did Nov 27 '16 at 10:23

Reopened

The relation between quasi-permutation matrix and permutation matrix?

Please review this Question with an eye to reopening. The post seems to me a self-contained request for terminology explanation, and the OP was certainly engaged with clarification and attempts to understand that explication.

Disclosure: I answered this Question with reference to the original literature, but likely one or more improved answers could be given by domain experts.

Reopened

This question was closed as duplicate although the question is not answered in the linked thread. Please vote for reopen.

Reopened

Can this question be re-opened? I'd be interested in seeing it answered.

Factor $ab^3-ac^3+bc^3-ba^3+ca^3-cb^3$

It was closed as a duplicate of another question, even though it specifically asked for a solution using a certain hint, and none of the answers to the other question or its duplicates, as far as I can tell, use the result in the hint.

• Interesting that at least seven people have posted questions asking for a factorization of this expression. That none of the many answers posted to the seven questions have hit upon the hint leads me to wonder whether there isn't some mistake here, that is, whether there is no way to make any use of the hint. – Gerry Myerson Apr 20 '17 at 13:15
• @GerryMyerson That's possible, but I think it's more likely that nobody has hit upon the idea that the problem setters had in mind. (The phrasing makes it sound very much like the kind of question that would have appeared on British university entrance scholarship exams in decades past.) And on previous questions, they wouldn't have been looking to do that. – user49640 Apr 21 '17 at 22:09

Reopened

Permutations with restrictions on item positions

The OP got what was needed from a Comment I left, and proceeded to ask this related Question. Once clarified the original Question was about efficiently counting certain restricted permutations, and the follow-up concerned efficiently generating them.

I find the original Q interesting in that the theorem of Valiant (1979) gives a "negative" answer and deserves to be more widely visible on Math.SE.

Reopened

Request for reopening: Open Problems in Semigroup Theory.

This question received 5 upvotes, a high score for the tag "semigroups", indicating some interest of the community, but it was quickly put on hold as too broad. Only one open problem was mentioned in a comment.

The question is certainly too broad if group theory is not excluded, but otherwise I am not so sure it is that broad. Anyway, since the OP is referring to Howie's book, one may restrict the question to semigroups in algebra, in a wide sense${}^*$. I know of a few existing lists of open problems on semigroups, but it would be useful to gather them in a big-list. All in all, I see this question as a frequently asked question and I think it is worth to reopen it, perhaps in a slightly different form.

$^{* \text{ For instance many questions on finite semigroups are closely related to profinite semigroups, which are topological semigroups.}}$

Reopened

A lot of context has been added to Binomial expansion going wrong!. I think it is a good question displaying a common pitfall when using power series expansions (and not only because I wrote an answer). I think it should be reopened, but I can't vote to open without unilaterally reopening the question.

Reopened

This question started out with a few close votes before the author showed their work, and ended up being closed. Now that work has been shown it probably deserves to be reopenend (esp since it is an instructive example of use of the mod Distributive Law - which deserves to be much better known).

• The question was not yet through the reopen review, which would likely have led to the reopening by itself. – Daniel Fischer Jul 26 '17 at 18:01

Undeleted

Please consider undeleting this post. Both the question and the answer seems quite interesting and is of high qualities.

• The Question was self-deleted on Aug. 14, a few days after it had been answered (and clarified in Comments on the Answer). I've upvoted the Answer so that self-deletion is no longer an easy option. – hardmath Aug 16 '17 at 13:56

Reopened

This question: What does it mean system of contractions $\textbf{with overlaps}$? was closed as unclear. While I do think the original version was lacking context, it was only unclear if you don't know what an IFS with overlaps is. I've since edited the question to add context and recommend it here for reopening. It does have 3 reopen votes but has been stuck there for a couple of days.

Reopened

I would like to request the following question be re-opened:

Poisson process with dead time

Earlier versions of the question were unclear and confusing. I edited the question heavily, removed extraneous text about Monte Carlo simulations, and also added a diagram for clarity. As it stands now, I think the question is quite clear. It also has an answer.

I would therefore request this question be reopened, or the close voters give more specific feedback about what needs improvement so I can improve it.

• For some context, the answer accepted after reopening reads, in full: "I would have thought $T_n−T_{n−1}$ would be i.i.d. between the the two methods and over time. My simulation in R seems to confirm this." Sorry but where are the mathematics? – Did Oct 4 '17 at 10:17
• I filled in the mathematics in my answer. Henry's "comment answer" got me on the right track. – Atul Ingle Oct 4 '17 at 14:47
• You are saying there is an answer to the question you asked but that it is not the answer you accepted? So sophisticated... – Did Oct 4 '17 at 15:11
• As I said, the "comment answer" did answer the question for me, so I accepted it, and I filled in the details. Perhaps I should accept my own answer instead? Or edit the comment answer to include my details? – Atul Ingle Oct 4 '17 at 15:23
• Well, at this level of departure from logic, I would not dare to give any advice... :-) – Did Oct 4 '17 at 16:44
• Since you have >1000x more reputation than me here I do really value your advice. It sounds like you are still bitter about name-calling, so I'd like to apologize again. – Atul Ingle Oct 4 '17 at 16:58
• No idea what you are talking about... but please let us leave it at that. – Did Oct 4 '17 at 17:10

Reopened, Reclosed, Deleted

I have edited this question, deleting the poster's opening statement about his hatred of statistics, which is off topic. It was closed as "primarily opinion-based". But the proper remedy was just to delete the initial opinion, and I have done that. The question remains intact after deletion of the off-topic opinion.

The content of the question is substantial and serious. Now that the off-topic personal remark at the beginning is gone, I propose that this be re-opened.

Why should statistics be considered mathematics?

Undeleted

I would like to request undeletion of Proof that $d^2 \phi = 2\pi \delta^{(2)}(r)dx\wedge dy$ in polar coordinates around a puncture?. I saw this thread recently in meta suggesting it is frowned upon to delete a recently answered question. In my case, I was in the middle of a lengthy edit in response to a request for clarification, and feel to have the rug pulled out from under me. Thanks.

I still have the tab open in my browser, although my response is hidden under an overlay. Is there any way to recover my work in progress?

• The question is probably deleted because there is a duplicate. The question should be closed anyway. – user99914 Nov 18 '17 at 6:48
• @John, it was deleted by the person who posted it, with no reason given. – Gerry Myerson Nov 18 '17 at 12:06
• @JohnMa So do you think it is not worth the effort to recover an answer to a question that is worthy of being closed? – ziggurism Nov 18 '17 at 13:41
• @gerry with Ted's comment that probably the reason. – user99914 Nov 18 '17 at 15:31
• @ziggurism it depends. Your answer is of high quality but there's already an almost identical one here. – user99914 Nov 18 '17 at 15:37

Reopened

Please undo the following duplicate link by reopening this question. The OP misread the duplicate and voted to close their question.

This question asks if the complex orthogonal group $$\{A \in M_{n\times n}(\mathbb C) : A^tA = I\}$$ has two connected component. The duplicate, however, is about real orthogonal groups. Worst still, the duplicate is also closed as a duplicate of another one, which shows that $GL(n, \mathbb R)$ has two components. Of course all the method employed there will not be useful in solving the original question, since $GL(n, \mathbb C)$ is connected.

Please undelete Exterior product with coefficients from finite fields. as I had an answer near complete when it was deleted.

• OP self-deleted the question after having been told it is unclear. It is not impossible, they'll come back with a clarified question. Until then I do not see the merit of undeleting as unclear as that one, especially when even OP somehow acknowledge it is unclear. – quid Nov 27 '17 at 15:00
• @quid So shall I delete my nearly completed answer? Start anew if the user decides to repost the question with clearer phrasing? – ziggurism Nov 27 '17 at 15:43
• I assume you could store the text somewhere (locally); if nothing else as a draft for an email or something like that. If no question is forthcoming in the near future you could use the work to create a self-answered Q&A pair. – quid Nov 27 '17 at 17:55
• @quid how could we tell if/when the user reposts the question? – ziggurism Nov 27 '17 at 17:57
• You can follow the activity of any user on their user page; in the present case here math.stackexchange.com/users/493344 You could also search for "exterior product" on the site; which is sufficiently distinctive to be helpful. I would not wait overly long, maybe a day or two. – quid Nov 27 '17 at 18:12
• Are you still requesting undeletion, zig? – Gerry Myerson Nov 30 '17 at 21:52
• @GerryMyerson to be honest, my unfinished answer is not quite in a state to be submitted. I hope to polish it up soon – ziggurism Dec 2 '17 at 0:39

Reopened

The question Need Examples to Understand Choice Function and Choice Structure is in no way a duplicate for the following question: (P(X),CR) may be a choice structure even if R is not a rational relation In the former I have asked people to provide me some examples to understand the definition of Choice function and Choice structure. In the other question, I have asked for an example to show that a relation underlying a choice structure should not necessarily be a rational relation. The only relation between these two questions is the definition included in the latter question to clarify the question. I though including the definitions will help people to understand my question! Would you please reopen my question or at least tell me how I can clarify the distinction between my question and request StackExchange to remove the hold on my account?

• Wouldn't an example of a choice structure in which $R$ is not a rational relation also be an example of a choice structure? – Carl Mummert Sep 20 '15 at 19:57
• @Carl Mummert, No, because in the former question, my problem was understanding the fundamental concepts. If you take a look at the content of the question, I have completely explained that. Providing the example for a choice structure based on a non-rational relation would not help me understand those concepts. The latter question is actually a proof, while the former one only need explanation and examples. – user2521204 Sep 20 '15 at 20:03
• I would recommend doing one thing at a time. If you want to understand the fundamental concepts, ask about them. If you want a non-rational structure, ask about that. But don't ask both at once. Also, it would have helped if you had explained the microeconomics context of these questions - they are not really about set theory, but few here are experts in economics, so people may not realize that is what you are asking about. – Carl Mummert Sep 20 '15 at 20:05
• It is probably worth mentioning that these questions were also discussed in a separate meta thread: meta.math.stackexchange.com/questions/21473/… – Martin Sleziak Sep 21 '15 at 9:44

Deleted (by OP), Undeleted

Matlab and the 3 Step Adams-Bashforth Method

I just noticed, that this question got deleted by the querist. It took me some time to answer this question properly, as it also contains some implementation in Matlab. IMO this question is not the best example for a question that should be asked on MSE. Still, this contribution might be helpful for other users struggling with similar issues.

If the community sees that differently, then the deletion is fine. But the OP should have never deleted that question in the first place, as he got help solving his problem, but did return nothing..

I suggest to change the title to "Why does the Adams-Bashforth Method converge for this ODE?" Better ideas?

Undeleted

Another day, another post deleted while I was halfway through a lengthy answer. This time it is Doubt on Do Carmo proof of Gauss Formula (Isometric immersion). It's probably a self-deletion by the original poster, but I spent some time on it, so if it's reasonable please undelete.

[Undeleted]

As I mentioned in the old thread, this is a reasonable reference request on whether Georg Cantor's (well documented) views on religion influenced his choice of notation. I think there are common misconceptions here, and this question may be a good place to at least start addressing them.

If undeleted, I think if nothing else we could collect the relevant comments under the question as an answer, although of course something more detailed would be even better.

(It would perhaps have made sense to edit the request in the old thread rather than posting this one here, but this is not possible since that thread was since closed as a duplicate of this one.)

• Now undeleted, but notice that while it was deleted it said, "deleted by Community♦ Mar 8 '14 at 13:28 (RemoveDeadQuestions) This question was automatically deleted." So I assume it's in danger of being automatically deleted again, unless, what, it gets an upvoted answer? I can never remember exactly what it takes to make a question safe from autodelete. – Gerry Myerson Jan 11 '18 at 9:50
• Yes, thank you Gerry. I'll try to post an answer later today if no one else does first. – Andrés E. Caicedo Jan 11 '18 at 12:41

Undeleted

This answer has just been deleted, and I was one of those who recommended its deletion through the review queue (as can be seen in the review history) because it was identical to the question, and thus seemed completely useless; but I realized afterwards that the question had been edited to match the answer after it was posted. I have rolled back to avoid other reviewers to be confused (see also the revision history of the question), but I suspect that the other reviewers voted for the same reason, as almost all the deletion votes have been given after the question was edited.

I think it's unfair to the answerer that the answer was deleted due to a subsequent change of the question. I thus suggest that this answer get undeleted.

• I undeleted. Even though the answer is not so great, but I see the point you want to make. – quid Apr 10 '18 at 15:12

Undeleted

The question Is the function from the coefficients of a monic cubic polynomial to its least root continuous? received an answer (from an experienced user) in half an hour after creation. However, OP self-deleted his question shortly after that. According to one of our site mods, this is an "abusive behaviour". Therefore, I propose to undelete this question.

• It seems that we edited nearly at the same time and our edits clashed. I have rolled back my edit. – Martin Sleziak May 2 '18 at 15:08
• @MartinSleziak Thanks for your time for editing this. Pasting the URL of the post used to show the title link. It seems that it no long works. I didn't know why there's no preview while I was writing this. – GNUSupporter 8964民主女神 地下教會 May 2 '18 at 15:12
• I have observed on occasion an inconsistent behavior of link expansion between the preview and the post. I am not really sure when it works and when it does not. Here is a test in the sandbox and link to the source. – Martin Sleziak May 2 '18 at 15:20
• @MartinSleziak Thanks for your answer. I've corrected this. – GNUSupporter 8964民主女神 地下教會 May 2 '18 at 15:29

Reopened

This question was initially primarily about implementing Newton's method in Matlab, and was closed as off-topic. But the specific polynomial exhibits some properties that makes it interesting from a mathematical point of view. The question has been reworded to be primarily about math, and the existing answer addresses the math question. I'd like for it to be reopened.

By the way, the question has been on the starboard for four days at Reopen? Undelete? Close? Delete?. I think most people interested in this meta thread would also be interested in that chat room.

Reopened

This question was closed as "unclear what you're asking." I edited it into standard mathematical notation so that the question is unambiguous. The question does not appear otherwise off-topic (I'll certainly accept having found the trivial solutions as context). The question interests me and I would like it reopened.

(I am unsure of why the review queue responded so negatively to the question)

• I said leave closed because it just said I found this and this without showing any work and then requested how to do it. To me, that is like saying what is some integral I found it to be x. We know they can probably use Mathematica to get the value so what have they really done? – dustin Mar 8 '15 at 18:06
• @dustin Thanks for your reply; it is good to get a response from someone who reviewed it. (I also realized, looking at the review dates, you would almost certainly have reviewed this revision, which has severe formatting issues too) – Milo Brandt Mar 8 '15 at 18:19
• I can't remember which version I saw. I just knew why I wouldn't choose reopen. If it said I did this with work and obtained this, I would have said okay. – dustin Mar 8 '15 at 18:21

Reopened

Topology of sets - prove or disprove the following statements was originally posted without any context or signs of effort. After others complained in the comments, OP actually fixed the question, explaining their thoughts on the problems, all of which were well-considered. This is a good outcome, all too rare, which we should encourage!

But then the question was closed anyway, belying the commenters who asked for clarification.

Let's reopen.

• I think only the last vote came after the edit, which appears to be an anomaly. (By the way, it is possible the review queue would have taken care of this. You could wait a while after voting to reopen to see if there's a reason to still post here.) – Jonas Meyer Mar 17 '15 at 15:20
• Just so that everyone knows, there are online OCR tools that convert images to text. You still need to correct the formulas, but it significantly reduces the time needed to do it. In this case, it took me about a minute (plus a few seconds to add linebreaks in the last paragraph). Compare the two scenarios: a question formatted like this one was arrives in the reopen RQ, vs. a question formatted like this one is now arrives in the RQ... – Najib Idrissi Mar 17 '15 at 15:32
• @Najib I would very much appreciate pointers to some of those tools; I spend a lot of time inlining scans and screenshots. – MJD Mar 17 '15 at 15:40
• I used onlineocr.net in this case, I only had to correct the formulas. I don't know how well it works for larger bodies of text. – Najib Idrissi Mar 17 '15 at 15:42

Undeleted, Redeleted

What was the point of deleting https://math.stackexchange.com/questions/106624/finding-an-f-automorphism-having-specified-the-images-of-two-elements ? Is the website really better without the mathematical content in the answer to that question, than with it?

• The question is unclear and missing context. It would be preferable, IMO, to start from scratch and post a new question with explicit hypotheses, since OP isn't around to clarify anymore. – Najib Idrissi Apr 10 '15 at 7:21
• The thread is quite confusing. I am not sure how I would vote myself. But, arguably, somebody interested in the subject is better served finding/reading something other than those posts. – quid Apr 10 '15 at 11:06
• Curious. It was autodeleted shortly after my vote undeleted it. – Matt Samuel Sep 5 '15 at 3:02
• Yes, that's very strange. I didn't think the Community user acted that fast, @Matt. – Gerry Myerson Sep 5 '15 at 6:23

Deleted

Recently a reference/book request question was put on hold as too broad. However, we have allowed and currently still allow these questions since older and newer questions aren't being put on hold. For this reason, I request books on math bio be reopened unless we are now closing all other book/ reference post as well.

• The question is unreasonably broad. OP does not even say anything at all about their general background in math. – quid Mar 8 '15 at 18:35
• @Quid that is exactly how almost all the reference request are. – dustin Mar 8 '15 at 18:36
• Then we should close them too. However, let me also add that the math background thing is less of an issue when somebody asks about, say, an intro to abstract algebra. But for this question it is really key to know of OP knows statsitics, (P)DE, dynamical systems, etc. or not. – quid Mar 8 '15 at 18:38
• For example that one, while really not great, is a lot more specific math.stackexchange.com/questions/1180720/… in that it mentions a beginning physics background. This one is better too math.stackexchange.com/questions/1180124/… – quid Mar 8 '15 at 18:40
• @quid when i am not on my phone i will link well received overly broad requests. – dustin Mar 8 '15 at 18:42
• Great. I will keep the close-votes handy. – quid Mar 8 '15 at 18:43
• @quid the complex one you linked should probably closed as dupe since there are a bunch on it. – dustin Mar 8 '15 at 18:44
• I don't know. Very possible. My point was only it gives a lot more details and background. – quid Mar 8 '15 at 18:45

Reopened

Relation between number of unique values in Gramian Matrix (G) and the matrices that created it got closed in spite of the clarifications made in the comments. The clarifications have now been incorporated in the post, and further improvements made. It should be reopened.

Reopened

Did marked my question a duplicate. Why is it a duplicate?

I think e is answering a question using a fact asked about in another question. How does that make my question a duplicate?

Before the marking, I got an answer and accepted it. That there was this really long answer that was unrelated to what was suggested by Did seems to suggest my question was not a duplicate.

Reopened

Please reopen Finding Nash equilibrium in game with random event at event tree?. After the first vote to close as duplicate was cast, the OP pointed out that this question is about a different game. This is immediately confirmed by a look at the image linked to in the post (which the OP can't include in the post due to lack of reputation). The question was nevertheless closed as a duplicate.

This is particularly unfortunate since it was good style on the part of the OP to ask a new question about this new game instead of continuing to ask me new questions in the comment thread under my answer to the old question. Closing this new question disincentivizes this constructive behaviour.

• I saw that question in the review queue, but it lacks any context for why the (new) game in question is of interest, so it would still qualify for closing under that reason, even if it is not a duplicate. – Carl Mummert Aug 13 '15 at 11:58

Undeleted, Reopened, Reclosed, Reopened

Please undelete this question because:

• Qiaochu Yuan's answer is of (very) high quality. It is relevant in many senses and canonical for this kind of problems (which are not so rare on the site).
• The two answers + OP totalise 33 upvotes and 3 downvotes. So apparently the question is appreciated by the community.
• Slightly ironically you link to your answer not the question, while not mentioning at all that one of the two answers is yours. (It is not possible to use at-notify in the way you seem to want to use it. Even if you are aware of this it is not a good idea to use the syntax as it can confuse others into believing it in fact does work.) – quid Aug 4 '15 at 17:00
• @quid you are right, it is because I copy-pasted the url and accessed it from my profile. I have no problem to mention that one answer is mine but I don't think that the question should be reopened because of that. Nevertheless I still think it should be reopened for Quiaochu's answer. – Surb Aug 4 '15 at 17:02
• @quid regarding the notification: ok I'll avoid that next time. – Surb Aug 4 '15 at 17:05
• A problem I see with that Q&A is that while Qiaochu's answer should be a good answer to the question "Is every natural number interesting?" or something like this, it appears it is quite explicitly not what is asked for. Rather the question is about one specific number. (I have not voted on this myself either way. Certainly, there are worse things on this site.) // Thanks for following up on my other remarks. – quid Aug 4 '15 at 17:12
• @quid If the question doesn't get reopened, maybe it could be a not too bad idea to create question fitting the answer and copy-past the answer in this question (everything in CW obviously). – Surb Aug 4 '15 at 17:14
• Yes this seems like a good idea (assuming something like this does not exists already, which I do not know). – quid Aug 4 '15 at 17:16
• I'm sorry but is the question no longer opinion-based? Did you do anything at all to improve the question? Note that the popularity of a question has nothing to do with its appropriateness for the website, and it's dishonest to simply add up the scores of the Q and each A, as someone can simply upvote all three -- does this mean that it's three times as popular? And if indeed this sort of problem is "not so rare", then I'm sure you can find a good example of question where Qiaochu Yuan's answer can be transferred. – Najib Idrissi Aug 8 '15 at 7:33
• @NajibIdrissi That's a good point, I'll try to improve the question this weekend. – Surb Aug 8 '15 at 15:00
• @NajibIdrissi So I tried to edit the question and hope it can be considered on-topic now. – Surb Aug 10 '15 at 13:06