# Requests for Reopen & Undeletion Votes (volume 07/2018 - 12/2020) [duplicate]

The purpose of this thread is to help focus the attention of the community on posts that may require reopen and undeletion votes. A request should be posted as an answer below (one request per answer).

Some guidelines:

• Please be polite, and respect the many different viewpoints in our diverse community. This goes for the person making the request as well as those commenting on it.

• There is a reopen queue. Please wait until a post has gone through this queue, before posting here. Notice that the first edit after the question is closed pushes the question into the reopen review queue if the edit is done within 5 days of closure, and so does a reopen vote. (If the review has already been finished, it is shown on the timeline of the question.) When in doubt, wait 24 hours after the last substantive action.

• To inform readers of the current (and past) states of the targeted post, please add the information Reopened or Undeleted at the start once the request has resulted in some action. (If the action is undone, add this too, like Reopened, Reclosed.)

• Do not only post a request, like "request reopening of link". Instead, make a case for your concern. Yet keep in mind that it can be easier to get your request handled if you try to frame it in a way that takes the feedback the post received into account positively rather then seeking confrontation. Also, try to improve the post before posting here.

• In case of "small" requests, like one missing vote, it can make sense to ask in chat instead of posting here. The room CURED is a reasonable place for such requests. The same guidelines apply there.

Earlier versions of this thread that served as a model:

• I edited the post inspired by a concern expressed in a comment.
– quid Mod
Jul 19, 2020 at 23:49

Undeleted, deleted, undeleted, reopened

Please consider undeleting and reopening this post: radical center of three circles.

This post clearly indicated an attempt and has a detailed answer.

Please consider undeleting and reopening this elementary question: On proving $$\sum_{k=1}^{2^n+1} \frac{1}{k} > \frac{n}{2}$$

OP had his/her thoughts on the problem and also added an attempt for verification in the post after interaction in comments with others. This question has also been edited.

• Did you check to see whether it's a duplicate? Looks to me like the kind of question that would have been asked before. Aug 23, 2019 at 12:20
• @GerryMyerson: I can only find a similar one. Since I have a very narrow definition of duplicate, I don't consider it as a duplicate to the mentioned one. Others may probably find closer one. One may close it as a duplicate if one does find one. But I would object the strong action of deletion of this post.
– user9464
Aug 23, 2019 at 18:02
• Asker account deleted, answer a brief hint, the argument definitely on the site numerous times, the specific variant a bit artificial. Why in the world should we keep that?
– quid Mod
Aug 23, 2019 at 21:08
• @quid Why the account deleted is a 'point to count' to support the deletion?
– user486983
Aug 23, 2019 at 21:59
• @Isa sometimes arguments are made along the lines of: "Maybe the post is not great, but OP made an effort and we should not discourage them via deletion." There are also glimpses of that in this meta post. Once the account is gone that caries rather less wait. Differently, it's not so much that it's a point for deletion, but it's a point less against deletion.
– quid Mod
Aug 23, 2019 at 22:08
• @quid I don't get it. Your previous comment suggested like 4 'bad' things about the post, so why to keep that.
– user486983
Aug 23, 2019 at 22:21
• @Isa I asked why we would want to keep the post. A common argument given is that we keep it not to penalize the person that asked it. This argument does not really apply in this case. Another argument is that the answer is good; Again does not apply. Still another argument we keep it for others users. But it seems unlikely to be useful, as the argument in principle is on the site numerous times and the specific version is a bit strange in a non interesting way. Thus, I still am at a loss why anyone would bother to keep that particular post. Surely there are plenty of better deleted posts.
– quid Mod
Aug 23, 2019 at 22:30
• @quid I may agree with you the day I had 10k :) with your mentioned points: answer a brief hint, the argument definitely on the site numerous times, the specific variant a bit artificial. Except your first point: account deleted. I don't see any possibility of me agreeing with that point.
– user486983
Aug 23, 2019 at 23:02
• Not exactly the same, but the question seems rather close to Prove this inequality: $\frac n2 \le \frac{1}{1}+\frac{1}{2}+\frac{1}{3}+...+\frac1{2^n - 1} \le n$. However, it's not suitable for merging - the bounds for sum are different, the other post has an answer rather similar to the one already posted. Aug 29, 2019 at 6:58

Undeleted, deleted, undeleted, deleted, undeleted

I nominate Optimization problem for routes for undeletion because the question asker self-deleted his question shortly after receiving an answer.

Undeleted, reopened, closed, deleted, undeleted, reopened

Please consider undeleting the following question:

Is $\int_1^\infty\frac{1}{\sqrt{\Gamma(x)}}\mathrm dx$ a rational number?

I agree on the reason for closing this question. Even though the post is somewhat strange in its wording it appears to be overall interesting for the community (as the upvotes outweigh the downvotes resulting in a balance of $$+6$$). Additionally, the integral appearing in the question is strongly related to the Fransén-Robertson Constant and might be of help as future reference for this topic (as a number of relevant posts is also linked with the deleted one).

The question has got deleted again. I have still my POV listed above and I would like to hear the reason for re-deleting the question.

• I voted to undelete, but I have to say, it's a highly undermotivated question. I could write down a thousand expressions evaluating to real numbers, and ask for each, whether it's rational, without giving any reason to think it is, or any reason to be particularly interested in whether it is. Jul 29, 2019 at 23:40
• @GerryMyerson I have to agree on this issue. And indeed, the motivation is clearly missing but what remains is a relation to an actual known constant, which is from my POV the only thing which makes this question worth keeping. Jul 30, 2019 at 10:03
• OP has shown no interest in the question, having refused the invitation to improve it. mrtaurho, I suggest you post an improved version of the question, and your answer, so the material won't be lost. Aug 11, 2019 at 23:13
• @GerryMyerson Thank you, for your response. I will do so, as soon as I have time! :) Aug 11, 2019 at 23:16
• I see, mrt, that you never did get the time, which is a shame, since (as I commented on the question the other day) I don't think the main objections to the question have been addressed. Aug 27, 2019 at 0:07
• @GerryMyerson I was rather busy. Additionally, I was (and still am) rather confused what to do about this question. It has been reopened two times and so posting a new question (even an appropriate) would be in fact a duplicate. So I decided to wait for now. Aug 27, 2019 at 0:14

Undeleted, reopened, closed-as-duplicate

Please consider undeleting and reopening the edited post: How can one show that $$\sum_{n=0}^\infty\frac{n}{n!}=e$$?

The user had difficulties in articulating his/her own thoughts. The elementary question in the post is clear. It is also clear from OP's comment and picture attached to the original post what the asker was thinking.

• You should disclose the fact that you made significant edits to the question after it was deleted. The question itself is a duplicate of this question (and probably has other, better dupe targets; I just happen to know the one I linked to since I interacted with it two years ago). I don't see a reason to undelete it.
– Xander Henderson Mod
Aug 28, 2019 at 12:31
• I posted a link to an exact duplicate under that thread. Pointless to reopen I think. Aug 28, 2019 at 18:59

Reopened

I have edited my post “Most intuitive” average of $P$ for all $x\in A \cap [a,b]$, where $A$ is countable and the average is unique? and waited for five days. Is it clear what I am asking? If not, could any suggestions be made?

Edit:

Users are trying to delete my post. If a post is unclear why would you to delete it? This is Math Stack Exchange, not Math Overflow.

I made more edits. Is it clear now? If not please explain. Offer one hint.

If you are wondering why I have a hard time explaining my post it’s because I have not mastered the concepts needed to explain this? I don’t care if this is worthless or gold. I don’t care if anyone steals this. I just want some guidance and most of my professors are too busy.

Second Edit:

I shortened the post to one question and a couple of paragraphs.

• Rahul commented on 21 August that you had a couple of equals signs where there should have been element-of symbols. You never engaged with that correction. Aug 30, 2019 at 0:06
• @GerryMyerson Correction made. Is there anything else? Aug 30, 2019 at 0:18
• I don't know. It's not my area, and it's long enough to be a PhD thesis. Sorry, but I won't be going through it in detail. Aug 30, 2019 at 2:32
• @GerryMyerson Users are trying to delete my post. Is this acceptable? Aug 30, 2019 at 21:22
• As Gerry has pointed out, your post is very long. Have you thought in splitting the content and ask many questions instead of only one?
– user486983
Aug 30, 2019 at 21:40
• Or you could also start a bounty :) I think you can set one for +150
– user486983
Aug 30, 2019 at 21:41
• I really don't know what to tell you. Maybe what's unclear is which of these many questions is the question: What is the "most intuitive" average of $P(x)$...? What do you think of these properties/examples? Are they reasonable? If so, how can we create a measure that suits these intuitions? And if not, how can we create a measure that suits better intuitions/intuitive examples/properties? So far, are my intuitive properties reasonable? If not, could we find the most "intuitive" Folner Sequence of any countable set? What would be the measure and average be? Aug 30, 2019 at 22:54

Undeleted, reopened

Please undelete and reopen this post:

How to show $$13\left(x^{2}+1\right)+\sqrt{2\left(x^{4}+1\right)}+62 x-\frac{45\left(x^{2}-1\right)}{\ln x}>0$$ for $$x\in(0,1)$$

Context for the question was added upon request by the asker, which has been lifted to the post.

Undeleted, reopened

Please undelete and reopen this post: How can one integrate $$\int\frac{1}{(x+1)^4(x^2+1)} dx$$?

OP wants to calculate this integral. He/she is not asking for a solution to this integral per se but states in the post his/her frustration on partial fraction decomposition (PFD) of the integrand. OP even has attempted to use something else (u-substitution) to solve this problem. Benard's answer addresses the difficulties of PFD without divulging the complete solution to OP.

Undeleted, deleted, undeleted, reopened, closed as duplicate, deleted, undeleted, deleted, undeleted

Please consider to undelete this question.

The OP brings some background about the problem and is just trying to find an easy solution. The one provided by me looks quite unknown (as it seems from the comments and the answers) thus I think it can be of future help if the question is undeleted.

• It's good form to disclose that one has an answer on the post oneself.
– quid Mod
Aug 15, 2019 at 21:00
• This question is a duplicate of many other questions on MSE. While I don't think that it is worth keeping (it brings nothing new to the table), if it is going to be kept, it should be closed as a duplicate. I left comments indicating a couple of potential dupe targets.
– Xander Henderson Mod
Aug 17, 2019 at 15:05
• On the contrary I believe it brings something new to the table. My solution is different than any other from all the linked posts. Aug 19, 2019 at 20:24
• @Zacky In that case your answer will stand its ground as an answer to the duplicate target as well, and you might consider relocating it there! Just by posting a new answer, the thread of your choice will be bumped to the front page, meaning that many viewers will see it and be able to vote it. <- This could be my template reply to all the users who are sad about a deletion of a duplicate. They can easily save their work this way! Aug 30, 2019 at 18:19
• "Partial fraction without defraction for an integral" What the heck does that mean? Is defraction really a word? Why has no one edited that title to something intelligible? Aug 30, 2019 at 23:00
• @GerryMyerson I think that no one had edited the title into something intelligible because no one actually knows what the asker intended. That is part of the problem with the question (aside from the fact that it is a duplicate).
– Xander Henderson Mod
Aug 31, 2019 at 14:17
• @Zacky Honestly, I think that Jyrki's advice is good advice. Indeed, I think that your answer would be a better fit for one of the other questions, if for no other reason than the current question specifically asks about partial fraction decomposition, while the others don't. Your answer would be a better fit for a different question.
– Xander Henderson Mod
Aug 31, 2019 at 14:18
• @XanderHenderson something looks off. You said that it brings nothing new to the table and it's not worth to be kept, you even ranted on how my answer isn't a "pedagogical". Are you sure that you honestly believe that is a good advice? Sep 1, 2019 at 8:52
• I also wrote in my pre-edit for OP: "Since this is just for your training, here's a more different approach for it. If it doesn't fit for you, I will delete it (it doesn't use any partial fractions)", when OP commented I think I received a positive feedback about it from OP.// Indeed it doesn't answer the exact question, but another answer (which got accepted by OP) shows a way with partial fractions. I only posted my answer after I saw it, and after the comments (from some high-rep users) who encouraged OP to not look for a better way? Sep 1, 2019 at 8:58

## Reopened

It was closed for the understandable reason that it lacked sufficient detail to be comprehensible by someone without Rudin's book to hand, and not only that, the reference to the book was inaccurate! But the poster, a newcomer, has carefully edited the question to provide more detail, and to correct the erroneous reference. Then, after waiting for five days, he asked politely if there was anything more he needed to do. Meanwhile, another poster had provided full details in a comment - whose length even provoked some controversy!

I don't think anything more needs to be done (unless someone with moderator privileges wants to edit the comment into the question).

• You certainly have those moderator privileges to edit the question, if you want to do that yourself. I also believe the length isn't the problem with that comment, but the fact that it contains those superfluous "begin quote" and "end quote". Perhaps by flagging a moderator is willing to edit that out, since otherwise it's an useful comment. Apr 17, 2020 at 15:13
• @Zacky Thanks for editing the question. Apr 17, 2020 at 15:53

This question was undeleted by 10 people then subsequently deleted and locked by a moderator. I request that such a heavy handed, unilateral action be undone since clearly many people disagree.

• Also the subject of math.meta.stackexchange.com/a/30914/8269 Apr 27, 2020 at 9:44
• Very poor post that is thankfully deleted. You should have considered keeping this poor answer deleted as well, @Matt. Sep 9, 2020 at 22:59

Reopened

I would like to see this question reopened. It is certainly not a duplicate of the previous question as here a double sum have to be evaluated. A partial answer ("the inner sum") which was considered in a comment as "promising" is in fact not helpful at all.

Undeleted, Reopened

Please undelete and reopen Proof of $$(1 + \delta)^{1/2 + \delta}(1- \delta)^{1/2 - \delta} > 1$$ for $$0 < \delta \leq 1/2$$?. Let it be known that I answered the question. The question should now have sufficient context.

Reopened

Please consider this question Prove that $$\gcd\left(n^{a}+1, n^{b}+1\right)$$ divides $$n^{\gcd(a, b)}+1$$ to be reopened. I answered the question. And more context has been given.

• You should, perhaps, note that you answered this question, and received a bounty for that answer. Hence you are not a disinterested third party.
– Xander Henderson Mod
Jul 19, 2020 at 14:25
• What's the point of undeleting the post after it is reopened? You have nothing to request. Jul 19, 2020 at 15:33
• @ArcticChar I didn't undelete it. Jul 19, 2020 at 15:34
• @ArcticChar I actually rather disagree. A record of the activity should be kept at least for some time.
– quid Mod
Jul 19, 2020 at 16:31
• I guess Shubhrajit just deleted another request, @quid (I don't have 10k to see what exacfly happened) Jul 24, 2020 at 4:18
• @ArcticChar I have deleted my request. Always my requests get downvotes. I answered and invested time for them. Why can't I just request for questions to be reopened which are answered by me? I don't want to make any further requests. I started to hate MSE for many reasons including bad and unfriendly behaviour from users. Jul 24, 2020 at 5:47
• @ShubhrajitBhattacharya You do get positive net votes for quite a number of your request, and quite a lot of your request resulted in reopening/undeleting, so I don't see why you seem to be upset.... Jul 25, 2020 at 7:14
• @ShubhrajitBhattacharya While it is fine to request reopening/undeleting of posts that you are involved, we suggest users to explain why actions should be taken. The reason "I have answered the questions/ I have spent time on it" is not a very strong reason. Jul 25, 2020 at 7:17

Reopened

I propose to reopen Which Combinations of Roots of Unity are Zero?, which is a perfectly phrased and interesting question of which I have no idea why it had been closed. There was some debate about whether the questioner meant to ask for real or integer linear combinations of the roots of unity, which is now settled by an edit – it’s about integer combinations. (But even the version with real coefficients would be interesting and worthy of this site, in my opinion.)

It would also be nice to hear from the ones who have closed the question or are in favour of leaving it closed as to why this question should be closed. I have not the slightest idea.

Undeleted, Reopened

I would like to request that this thread be undeleted and reopened: "If $$\#(S)<\#(\Bbb N)$$, then prove that $$S$$ is finite, without using the Axiom of Choice.." I did not answer the question, but I think the thread is useful for people to learn which argument relies on the Axiom of Choice, and which does not.

• I am confused why my undelete vote wasn't there. Maybe I forgot to vote myself. What a blunder! I might have forgotten to vote to reopen too. However, I might also have voted to reopen, but the reopen vote might have also expired. Jul 29, 2020 at 11:53

Why is the the number of regular payments with a balloon payment n-1?

Again, people who are unfamiliar with actuarial mathematics are taking legitimate questions in this area and closing them as not being about mathematics.

Let me be clear: either remove the actuarial mathematics tag entirely and specifically prohibit this entire topic as being suitable, or stop closing questions that are well-understood by those of us who actually know the material.

• Ross Millikan has commented in that post, explaining how they think it is not about Math. Do you care to explain why Ross is wrong? Aug 18, 2020 at 4:20
• This seems like the wrong place to talk about how well understood, or not, the actuarial-science tag is -- you should write a question for meta where it'll be seen by more people :) Aug 18, 2020 at 5:24
• Regardless of one's perspective on actuarial mathematics, it's important to note that the OP doesn't provide the key definition of what they're not understanding here. Providing definitions is a basic step in providing context for questions on MSE and the fact it's missing here is why I voted to close this question. Until that's fixed, I don't think it should be reopened. Aug 18, 2020 at 5:32
• The question has been deleted. Sep 1, 2020 at 22:49

Locked, Unlocked

Please reopen this thread: Given $$n$$ integers $$p_0, p_1,...,p_{n-1}$$, what is the smallest possible degree of a polynomial $$p(x)$$ such that $$p(i) = p_i$$?. I answered it (although it is now a community wiki post), but the thread is very much self-answered.

I think the thread is useful. There are many questions of the form: "Given a part of a sequence $$a_0,a_1,a_2,\ldots,a_{n-1}$$, determine the value of $$a_m$$ for some integer $$m\geq n$$." I personally dislike such questions because the given information is not sufficient, but with the added assumption that the sequence is a polynomial sequence (of degree at most $$n-1$$), then such questions become answerable, and we can use some idea from the thread above to establish answers to such questions.

• Interesting to see a moderator joining an edit war... Sep 4, 2020 at 17:29
• @ArcticChar That is why I think the moderator's actions were inappropriate (whence the complaint in Math Mods' Office). Sep 4, 2020 at 17:44

Closed. Edited. Left closed. Deleted.

I think this post (it was closed!)

Alice Through the Looking-Glass: is there a mathematical description of this infinite regression paradox?

I added images and a formal example.

The question is about some properties/abnormal behaviours of functions (/transformations). I want to know if there are known examples, if they are studied, if they are formulated and etc.

I am aware that it's not the best and most usual and most non-controversial question... but I think it has its own good sides!

Maybe someone can help to reformulate it so it won't be connected to Carroll's book? (Although the basic and most general premise is heavily connected)

I want to ask about functions/transformations that can lead to similar abnormal/paradoxical behaviours or results and if there're famous examples or how mathematicians deal with them and etc.

Closed, Deleted

Please consider undeleting and reopening the post (question & answer both): Why integral of $$dx$$ is not $$∫dxdx$$.

This is a basic question came to OP's mind on the subject. There are a lot of people who have the same doubt about the fact. It will be very much helpful for those. Also my answer was accepted by OP and also being appreciated by the other members on this site. I think those question and answer are suitable for the site. I strongly recommend to undelete the post.

Undeleted

vertices on a path received one answer, but the question asker deleted his own question. This is an abuse of the system. Please undelete this question.

Please consider reopening How to intuitively understand the $n$-dimensional cube as the dimension grows large (or suggest a more suitable duplicate target—I was unable to find one). I would like to add an answer that would be inappropriate at either of the suggested duplicates, which are both mostly concerned with visualizing 4-dimensional cubes and not on developing intuition for large dimensional cubes.

• Um.... weird situation. While I agree with the OP that the duplicate do not compare the $n$-balls and $n$-cubes, they actually accept an answer that IMO completely ignore this aspect. Dec 23, 2020 at 17:01
• @ArcticChar I don't know why the OP decided to accept the one answer that was given before the question got closed, but they might still be open to reading additional answers. Even if not, future readers with the same question might be interested in other answers. Dec 23, 2020 at 20:19

Undeleted, reopened

I humbly request undeletion and reopening of this question, if you see fit to do so, because

a) reasons for closing should be derived from the question itself and not from speculation about the skills of the asker.

b) the given reasons for closing are incorrect - while the question sails close to an open problem, it asks a different but related question - it asks if the open problem (which relates to a series of polynomials) can be extended to its limit point.

c) the time from entering the reopen queue to deletion was less than two hours, denying any who might have been interested in its reopening the opportunity to declare the same.

d) moreover, I think others will find the question and any prospective answers of interest and value.

• The time from entering the reopen queue to deletion may have been short, but the question had been on hold for five days already. As for the close reasons, I'll note that 2 of the close voters did not use "not math". I think that personnally I would have probably voted to close as unclear what you're asking, because on a first reading I honestly had no idea what you were talking about. Dec 1, 2018 at 12:43
• @ArnaudD. Yes, but the reopen request followed an edit which increased focus on the actual question and removed the motivation for it, when I believe the question's motivation was almost certainly the cause for the down votes and closure in the first place, rather than the question itself which stands alone. Dec 1, 2018 at 12:47
• By the way, I think the most recent edit on your question (post-deletion) already makes the question more interesting. It only consists of adding a Wikipedia link, but that link already explains some of the context better than your question (for example, I hadn't realized that you were talking about polynomial bijections $\mathbb{N}^k \to\mathbb{N}$, but maybe that's just me). Dec 1, 2018 at 12:57
• For what it's worth, the reopen review was completed before the deletion, as one can see here. Dec 1, 2018 at 13:15
• @ArnaudD. good point, although predominantly the same users. Is there a better review link that shows timings etc.? I thought I saw one before but can never re-find it. Dec 1, 2018 at 13:39
• There's the timeline, but I don't know if it is as detailed as you'd want. (By the way, there's another question about how to find it). Dec 1, 2018 at 13:44
• Setting aside all other issues, there are some obvious (and, I think, easily correctible) errors in your question's key equation, stating the F-P conjecture: the right hand side has no $y$ in it, and the index of summation $n$ appears nowhere in the expression being summed. I'm pretty sure you want the summation to go from $k=1$ to $n$, not $n=1$ to $k$, with $f_n(x_1,\ldots,x_n)$ on the left hand side, not $f_k(y)$. Dec 1, 2018 at 15:28
• @BarryCipra thank-you. I think I intended $y$ to be the set $\{x_1,x_2,\ldots x_k\}$ and yes, I agree I appear to have exchanged an $n$ with a $k$ but alas no edits are allowed on a deleted post so I can't correct it :( Dec 1, 2018 at 18:17
• @RobertFrost That's surprising. In any case, I've just done the correction. Dec 1, 2018 at 18:57
• @ArnaudD. Thanks and you even got the $f_n$ I thought might get missed. Dec 1, 2018 at 19:00
• What do you mean by "timings"? The time of the review is there exactly. As usual, hover over the time stamp to get a resolution to the second.
– quid Mod
Dec 1, 2018 at 23:44
• @quid thank-you. That probably covers it although I can only see a deleted post on desktop so I'll have to check later Dec 2, 2018 at 4:07
• @ArnaudD. Thank-you for the edit. A reopen vote would be greatly appreciated (only if you think it appropriate). Else the deleters will reverse the undeleters! Dec 3, 2018 at 10:39

Please undelete https://math.stackexchange.com/q/2192864/290189 because OP has self-deleted his question one minute after receiving an answer from me. This is an abuse of the system.

• OP shouldn't have deleted it, but what a miserable excuse for a question! With all due respect, I don't think you should have answered it, not without first getting OP to bring it up to standards. May 24, 2019 at 2:47
• The question was deleted one minute after receiving an answer, but this request was posted more than two years later. If the asker deleted the question to cover up the fact that they got help, then they already succeeded. I don't really see a reason to undelete this, because it would just get closed and deleted again.
– user296602
May 24, 2019 at 6:42

Deleted by a moderator

This question was closed and deleted with the reason given "This question is missing context or other detail". However the author of the question explained both his educational background (he is an undergraduate) and his motivation for the question (it was information that wasn't covered in his degree).

This information is sufficient context to give an answer, indeed I can't think of any further context that a person asking the question could add that would result in a better answer.

• The body does not even contain the question. That question-post is poor, and the thread of very limited value overall. The answers being pretty terse and not giving enough detail. // Added: Given the comment below I'll add that it was not I that deleted it.
– quid Mod
May 9, 2019 at 6:59
• As far as I can tell, if a post was deleted by a moderator - like in this case - the deletion cannot be reversed by regular users. (Of course, voting your posts still can show to which extent users support undeletion - and if there is some support, perhaps moderators might have a look at the the question again.) May 9, 2019 at 6:59
• @quid can you explain what is poor about the question? Broadly speaking pen and paper methods of factoring numbers is a subject that the site should have coverage of. May 9, 2019 at 23:32
• I already mentioned one shortcoming. Further and more drastically, the question does not contain any relevant thought of the OP or even just explanation what they want that information for. For example, do they realize that one can easily recognize that some number are not prime? How would they approach the problem for two digit numbers? Or something else, would all make the question better. That said, the question would arguably be saveable. But what for? The answers are low quality. I'd prefer somebody, say my students, won't find any information here rather than those answers.
– quid Mod
May 10, 2019 at 9:55
• Fortunately similar information is available in other and better threads. In my opinion, the site is quite simply better without this thread.
– quid Mod
May 10, 2019 at 9:57

Please unmark the duplicate of this question. I have clearly said that my question has nothing to do with duplicate one. I am asking totally different thing and the duplicate question's answer does not help me at all. It is also an unique question which follows m previous question.

• I don't believe the relationship between the Questions is quite so simple as one "has nothing to do with" the other. Both involve intersections between two spherical caps, although you might not have visualized your problem in this way. There might still be a further problem in stating the area in terms of how you parameterized the spherical region, I grant, but it would be worth understanding the solution of the proposed duplicate to try restating the area given there in your terms. Jun 6, 2019 at 17:11

Undeleted, closed, deleted, undeleted, redeleted

I nominate Solve the recurrence $$\sqrt {x_n} − 5 \sqrt {x _{n−1} }+ 6\sqrt {x_{n−2}} = 0$$ for undeletion because OP has self-deleted his post shortly after receiving an answer. That's rude to the answerer.

• I agree that the question should not have been deleted by the original asker, and would have voted to undelete had I seen this before the question was undeleted. That being said, it is a pretty low quality question, and would like to now nominate it for closure and (if it is not improved) eventual deletion.
– Xander Henderson Mod
Nov 12, 2018 at 23:26
• @XanderHenderson Agreed and updated the status of my answer. Nov 13, 2018 at 1:27
• It is inconceivable this question is undeleted. Even the answer is pretty low-quality. Jun 26, 2019 at 4:53
• I find that revision history really surprising : one (now removed) user voted to undelete and then close the question, OP initially self-deleted the question but 5 days later voted to undelete after the second deletion, and now you've voted to undelete and then redelete the day after. Pardon my French, but WTF? Jun 27, 2019 at 9:31

Please consider undeleting this post: Integral $$\int_{0}^{2\pi} \ln (2\sin(\frac{x}{2}))dx$$

Whether the asker should articulate more details in "I've tried some substitutions" could be debatable for reopening the post; I do not think it should be deleted. There have been two answers, one of which has 11 upvotes.

• The question was on hold for a week without modification before it was deleted. The answers are fine, but standard, and don't rise to the level of exceptional. I see no reason to undelete this question. The asker clearly got what they wanted, and I don't see that question providing any lasting value to the site.
– Xander Henderson Mod
Jul 2, 2019 at 0:46
• The lasting value to the site, like many other posts, is that there are two good answers to a tricky calculus question, which is not only useful for the asker but also future readers.
– user9464
Jul 2, 2019 at 1:48
• The first part of your reply to me does not contradict what I said: you say that there are two good answers, I said that there are no exceptional answers. As to use to future readers: I disagree. This is a specific integral which can be analyzed using relatively standard techniques. The question itself is not terribly searchable (it is only going to come up if someone wants to deal with that specific integral (e.g. they are assigned the same problem as a homework exercise, and are trying to cheat), and the answers are not of any general interest (they are standard, but not general).
– Xander Henderson Mod
Jul 2, 2019 at 1:53
• Disagree. "This is a specific integral which can be analyzed using relatively standard techniques. ... the answers are not of any general interest " does not justify the deletion. MSE is not MO: most, if not all, of questions here "can be analyzed using relatively standard techniques". For instance, this recent question that has two good answers, the accepted one written in detail nicely by you, is a rather "standard" one. I would certainly not vote to delete such posts. (In case of any possible confusion: this is NOT sarcasm.)
– user9464
Jul 2, 2019 at 2:48
• It is funny that you pick that example. I downvoted that question, and voted to close it. It was not closed, and the other answers were, in my opinion poor answers (as they failed to address the key point, which is that an induction proof is needed somewhere). If the question is not going to be closed and deleted, it should at least have a correct answer. I would still be happy to see that question closed, and would not object to its deletion---my answer is nothing special, and doesn't (IMO) rise to the level of exceptional.
– Xander Henderson Mod
Jul 2, 2019 at 2:56
• Moreover, applying standard results to a specific problem is very different from demonstrating the correctness of standard results then leaving it to the reader to apply that result to their specific problem.
– Xander Henderson Mod
Jul 2, 2019 at 3:01
• Well, (1) I have done my proposal for undeletion. Readers can make their own decisions. (2) I will object strongly the post I just mentioned being deleted, considering the quality of your exposition and egreg's good answer. (How do you find the review history by the way?) (3) ... have to leave now.
– user9464
Jul 2, 2019 at 3:13
• Probably a duplicate of one or more of math.stackexchange.com/questions/815762/… and math.stackexchange.com/questions/889902/… and math.stackexchange.com/questions/679233/… and math.stackexchange.com/questions/2656431/… and also comes up in any question containing the name "Clausen". Jul 2, 2019 at 3:20
• @Jack To find the review history I go to the timeline of the post and then click on the link to the review event there. I don't know if there's a quicker way.
– user279515
Jul 2, 2019 at 6:41
• @GerryMyerson: having read your links one by one, I would probably not called the post a duplicate of those, although they are related to the Clausen function. (Never known this before, thanks for mentioning it.)
– user9464
Jul 2, 2019 at 11:47
• @Brahadeesh: Thanks for that. One can indeed use math.stackexchange.com/posts/3143084/timeline
– user9464
Jul 2, 2019 at 11:56
• It's funny how those who voted to close/ delete are here on this site for a while, and even claim to know that the question is easily searchable. Yet, instead of trying to mark it as duplicate, they simply delete it. Also it's quite bold for a single group of people (CRUDE users) to decide that it has no value for this site. Jul 22, 2019 at 8:50
• @XanderHenderson I wrote above in the third person since you're not the only one who believes that, but since you commented it here, can you please tell me why haven't you tried to mark it as duplicate (if it's easily searchable) and simply decided to remove the content? (maybe there's a reason that I'm missing). Jul 22, 2019 at 8:58
• -> Before voting to delete, please check whether there are any good answers; if so, then the question should be flagged for moderator attention as a potential merge candidate. We don't like to lose great answers!. And the answers provided there are definetly good. Thus those who deleted it violated the "rule" that I copy-pasted. // A little off-topic, but I hope that you are aware that who asked the question couldn't care less if the question is deleted since he/she already took the informatio needed. Thus by deleting the question, it even helps that user instead of penalizing them. Jul 22, 2019 at 14:00
• -> Of course, the posts around here aren't only for those who asked, but for the whole community. I fail to see why there ins't a way to penalize the users (for example a "question ban" if the questions previously posted are bad), but instead the decision that CRUDE users took is to penalize the whole community by erasing good content. Anyway, it's pointless if I type here in the comments, soon I will try to make a meta post about something related to this. Thanks for your time and have a nice day! Jul 22, 2019 at 14:12

Undeleted, reopened

Please consider undeleting and reopening this post:

where OP gave his/her thoughts:

Honestly I have no idea about how to approach this problem. I tried the expansion of $$\sin x$$ on the left hand side and then expand $$\cos x$$ on the right but end up with a mess. Then again $$\cos x=(\sin x)'$$, but by converting each term on the right hand side into derivative of sine does not give any sensible identity to draw out something. Really out of ideas on this one. Is there any way to do this? Please give me some hints. Thanks for your time.

Undeleted, deleted, undeleted, deleted, undeleted, deleted, undeleted, delete (mod)

Please undelete this post Map subset of a group to zero?

This is not a trivial exercise. It has a very detailed thoughtful answer by @Arturo Magidin.

Mod comment (quid): I deleted this one, as the question-post is still not clarified and the thread including the answer post is a back and forth. Like: "It cannot be this, you may mean that. Oh, now you said it's about something else." I am glad that OP was helped, but I think there is no archival value to this in its current form. As usual, those that want to can extract whatever they think is valuable, via edits or moving of content.

• If you plan to keep saying things like "Redeleted (6/17/19) by a same group of users. One initiated three times the delete votes and one voted three times to delete this post. – Jack Jun 17 at 22:01" you might refrain from voting to undelete repeatedly, especially on posts where there was not recast delete vote prior to that. (There is now though.)
– quid Mod
Jul 13, 2019 at 15:43
• There has been no action whatsoever (to my knowledge) from mods or the system to prevent casting/initiating deletion votes for some particular posts over and over again by mostly same group of users. It is not difficult to count such instances. I assume from such observation that repeated voting is not discouraged in general. "If you plan to keep saying things like" This is an absurd and highly misleading comment from a moderator: your quoted comment refers to one particular proposal and I have never said it somewhere else.
– user9464
Jul 13, 2019 at 18:09
• I take it you do not plan to keep saying things like the one I quoted, then. Well you did say "On the other hand, what one can see from the timeline is that a user voted to delete the posts twice while there are people who hold different opinions have already voted to undelete and reopen the post." which also raises double-voting in a critical way.
– quid Mod
Jul 13, 2019 at 18:57
• There has been no action whatsoever from mods or the system to prevent casting/initiating undeletion votes for some particular posts over and over again by mostly same group of users either. Jul 14, 2019 at 16:26
• @quid I think a mod deletion was highly improper here. Sad to see you once again forcing your personal opinions onto the community. These decisions should be made by the community - not an individual. Aug 4, 2019 at 15:24
• @Bill after about ten changes of status I think it's about time somebody decides it one way or the other. Visibly the community did not reach a solution.
– quid Mod
Aug 4, 2019 at 15:26
• @quid "Changes of status" are not harming anything. There have been more in the past and they eventually settled down. Aug 4, 2019 at 15:27
• @Bill it's a distractions, possibly confusing, and bumps this meta post. Certainly there are worse things, but I consider it as fundamentally unreasonable to have "blinking" posts that are un-deleted every other day or every other week. (This one is going on since a month.)
– quid Mod
Aug 4, 2019 at 15:29
• @quid I think there are for more important matters that deserve to be deemed "fundamentally unreasonable". This shouldn't even be on the radar. Aug 4, 2019 at 15:32
• @BillDubuque examples?
– quid Mod
Aug 4, 2019 at 15:33
• @quid One of the reasons that I initially created this thread (original version) was so that there would be only one thread being bumped on such matters. The bumps are expected and are completely normal. Those with no interest in such matters can easily ignore it. Aug 4, 2019 at 15:42
• @BillDubuque that's fine it does however not address the other points and does not provide any examples. Anyway, if you see things that I or another moderator should address please bring them to our attention. If you want to discuss this particular post in more detail, post a question about it.
– quid Mod
Aug 4, 2019 at 15:49