# Requests for Reopen & Undeletion Votes (volume 07/2018 - today)

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 was put on-hold pushes the question into reopen review queue, if the edit was done within 5 days of closure. So does a reopen vote. (If the review has already been finished, it is shown on the timeline of the question.) 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 once the request resulted in some action the information Reopened or Undeleted at the start. (If it the action is undone, add this too, like Reopened, reclosed.)

• Do not only post a request, like "request reopening of ". 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 in a away that takes the feedback the post received into account in a positive way 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 CRUDE is a reasonable place for such requests. The same guidelines apply there.

Earlier versions of this thread that served as a model:

Reopened

Could we please reopen: How might I define a parabola in vertex form, such that…

The OP has made an effort to improve their question. They have clarified the question by including the vertex form of a parabola for future reference, and have also added MathJax to the question. I have also cleaned up the tags to better reflect the question ('linear-algebra' was not appropriate).

The question is perfectly clear, and the OP has given the background to their own question which makes it perfectly answerable.

• I have voted to reopen, but I note that the question already has an accepted answer. – Gerry Myerson Oct 12 at 6:47

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 Aug 15 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 Aug 17 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. – LeBlanc Aug 19 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! – Jyrki Lahtonen Aug 30 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? – Gerry Myerson Aug 30 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 Aug 31 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 Aug 31 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? – LeBlanc Sep 1 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? – LeBlanc Sep 1 at 8:58

Reopened

Please consider reopening Minimal surfaces under conformal parametrizations - proof verification

It appears to have been closed after the user vandalised their question (rolling back the question would seem like the better approach, which I've done) and appears to have plenty of context and be a reasonable question asking for help.

I answered question in this post, and I do not consider it missing context at all. OP summarized his/her attempt succinctly in the post: "Finding the roots seems complicated." (If one can find the roots $$a$$, $$b$$ and $$c$$, one can of course plug them into the expression $$\log_3(a)+\log_3(b)+\log_3(c)$$ to find its value. This is a natural attempt. OP did not notice that one does not need to solve the cubic equation in order to solve this problem.) Such attempt is by no means "I tried to solve this problem myself, but it seemed complicated."

• I will reiterate the comment I left before the question was deleted: I have read the question. The comment you cite does not seem to provide much context. Nearly any question on this site could be finished with the line "I tried to solve this problem myself, but it seemed complicated." Appropriate context would be, for example, a description of where this problem comes from, and what the asker is studying right now. A presentation of potentially relevant theorems and definitions would also provide context. – Xander Henderson Sep 30 at 19:00
• Moreover, the question has also been negatively received (while I don't usually consider voting on a question to be terribly compelling, it is a factor which should be considered), and neither of the answers is terribly compelling (J.G.'s answer has the advantage of being concise, while Jack's answer seems like overkill to me---why invoke Vieta's formulae (the question appears to be a question one might find in an elementary algebra class, though that context is missing; Vieta is, to the best of my knowledge, not generally taught in these kinds of classes). – Xander Henderson Sep 30 at 19:06
• Finally, @Jack, you insist that the question has context because the asker stated "Finding the roots seems complicated." Let us grant, for the sake of argument, that this is context. I do not see how it is sufficient context. Better context would be an indication of what the student is studying and and what level; a reference for the problem; a discussion of what theorems, definitions, or other results they know; etc. The point of asking for "work done" is to get an indication of the level of the student. In this case, knowing that they tried to find the roots doesn't give much insight. – Xander Henderson Sep 30 at 19:11

Undeleted, reopened

Please undelete and reopen this post:

How can one use the direct comparison test for $$S=\sum_{k=1}^{\infty}{\frac{1}{\sqrt{k}+10k}}$$?

Even in the very first version of the post, OP states his/her thoughts and difficulties he/she has. This post is NOT missing context. And it is NOT a duplicate of any other question.

• Because we already have many questions where divergence of a series is deduced from a comparison with the harmonic series, this is bound to be a duplicate dozens of times over. Therefore the question should also be closed as too localized (not adding anything new to the site, and only helping the asker do their homework). Missing context is the best proxy we currently have, so if reopened I will vote to reclose and redelete. – Jyrki Lahtonen Sep 30 at 4:53
• @JyrkiLahtonen Maybe I should have trie to search a bit more, but by a quick search I only found this: Calculus II: Comparison Test for Divergence $\sum\limits_{n=1}^{\infty}\frac{1}{n+\sqrt{n}}$. (All I am saying that I am unable to confirm that there are dozens of posts which are close to duplicates. Although I agree that when I saw the question, I expected that there should be many similar questions.) – Martin Sleziak Sep 30 at 8:09
• @MartinSleziak It is one of the standard series to use a comparison test with :-) Anyway, when the question is a (near-) duplicate IMO showing effort/thoughts is NOT SUFFICIENT to stop closure/deletion. The questions should have wider interest, and the context should demonstrate that. – Jyrki Lahtonen Sep 30 at 9:59
• Mathematics Stack Exchange is a question and answer site for people studying math at ANY level and professionals in related fields. How many questions a student asks are not supposed to be "standard"?! And is any one of the four mentioned in the first comment not standard? – Jack Sep 30 at 11:59
• @Jack Your comment about MSE being for questions at any level is a red herring---the question was not closed because of its level. The question is a standard question which occurs (in one form or another) in many elementary texts on calculus. Moreover, it is a question which already has an answer on MSE. What new, valuable information does this particular question add to MSE which isn't already on the site? – Xander Henderson Sep 30 at 20:18
• How many questions a student asks are not supposed to be "standard"?! @Jack, not very many. The same applies to StackOverflow. Which is exactly why Jeff Atwood wrote that a new asker should spend 98% of their time on StackExchange searching. Getting more and more questions does not improve the site, and is not necessary for its success any longer. On occasion it is quite the opposite. – Jyrki Lahtonen Oct 1 at 14:06

Undeleted, closed, deleted, undeleted, deleted

I think there's a consensus that we undelete questions when they are deleted by the user who posted them after someone else has posted an answer (see, for example, the comment here. In accordance with that consensus, I propose undeletion of this post:

Solutions to $$\sum_{j=0}^k r_j^2+3r_j+2\equiv 0 \mod p$$

Now I'll own up that I'm the one who posted the answer to the question. My answer was exceedingly terse, and came out of a review with the note, "This does not provide an answer to the question (and so on, and so forth)." But it does provide an answer. The question was to prove or disprove that there are no solutions to a certain equation (congruence, actually, but never mind), and my answer gave a solution.

• Is this actually a consensus? – Did Jul 23 '18 at 12:30
• @Did, if you look at the previous edition of this thread, you'll find that in April-May, GNU Supporter posted 4 requests for undeletion, all on the grounds that OP had deleted a question after receiving an answer, and all four questions were undeleted. – Gerry Myerson Jul 23 '18 at 12:51
• Yes, and?   – Did Jul 23 '18 at 18:11
• @Did For what it's worth, I have the same impression about the consensus. Preventing an asker from covering up their own question seems to be something the community values, even if it's closed later. – user296602 Jul 23 '18 at 18:35
• @T.Bongers (and also Gerry Myerson): I think that there is a moderate consensus that it is bad form to ask a question, get an answer, then delete the question. It belies an ignorance of the functioning of the site (i.e. questions are supposed to be helpful to everyone, not just the one person asking the question). However, in this particular case, the question is of pretty low quality, and should be closed and deleted (in my opinion). It seems like a waste of resources to have opened it back up again... – Xander Henderson Jul 23 '18 at 19:00
• For what it's worth, I have expanded my answer to the question on main. – Gerry Myerson Jul 24 '18 at 0:34
• "For what it's worth, I have expanded my answer to the question on main." On this topic, my understanding is that the consensus is that a good (or even great) answer is not really enough to justify keeping a poor question around. This and this are relevant. – Xander Henderson Jul 24 '18 at 13:27
• @Xander, the highest-voted answers and comments on your first link hardly support your understanding. The second link, even there there is considerable support for not deleting questions with good answers. I'm not convinced there is, was, or ever will be a consensus on this issue. A majority, maybe, but no consensus. – Gerry Myerson Jul 24 '18 at 21:31
• @GerryMyerson I think you and I must be reading very different answers. In answer to the question of whether bad questions with good answers should be preserved, my reading of the top three answers ((1), (2), (3)) suggest that it might be worth protecting a poor question if it hosts an excellent answer. – Xander Henderson Jul 24 '18 at 22:54
• On the question of upvoting poor questions with good answers, the top voted answer is this one, essentially "I don't do it, but there could be an argument in favor of it." The second answer is similar, with the idea being that a good answer should be preserved if it might be helpful for others in the future. – Xander Henderson Jul 24 '18 at 22:55
• In both cases, it seems clear to me that the consensus is that it might be reasonable to preserve a poor question if it attracted a really good, useful, generally helpful answer. Again, a good answer (or possibly even a great answer) is not, by itself, enough to preserve a poor question. – Xander Henderson Jul 24 '18 at 22:58
• Finally, I note that I made my initial comment in response to your assertion that you have improved your answer. Are you further asserting that the improvements created something that is of such lasting value that it will be beneficial beyond asking that poor question? Despite the fact that this question and answer have been the topic of discussion here for a couple of days, your answer has not attracted any upvotes... – Xander Henderson Jul 24 '18 at 22:59
• @Xander, I'm not in it for the upvotes. I objected to a user posting a question and then deleting it when it got an answer, as I agree with a moderator that such an action is an abuse of the site. Once the question was undeleted, I took the opportunity to improve my answer, in response to a comment from another user. What's wrong with that? I'm not asserting anything about the lasting value of the question or the answer, other than the answer being fuller now than it was. The answer may help someone coming along who is interested in sums of two squares modulo a prime. Fire away. – Gerry Myerson Jul 24 '18 at 23:30
• @GerryMyerson: it isn't pleasant to see one's own answer deleted, but in this case the question is clearly not up to many users' standards, so I think it is not surprising to see it deleted. At this point, the question is no longer deleted by the OP, but by several other users. – Carl Mummert Aug 5 '18 at 21:06
• @Carl, it isn't pleasant to see any answer with nonzero mathematical content deleted. More to the point, I would not have put the question up for undeletion, had it been deleted by votes of users. My objection was to OP abusing the site by deleting the question after getting an answer. I thought that was clear. – Gerry Myerson Aug 5 '18 at 23:09

Undeleted, reopened

Please undelete and reopen this post: Evaluate this limit: $$\lim_{n \rightarrow \infty} \frac{n\sin n}{2n^2 - 1}$$

This post is by no means missing context. OP clearly stated at the beginning what he/she tried and where he/she got stuck. This post has also a detailed answer by a 50K+ user.

• It might be worth noting that unfortunately that so-called detailed answer completely ignores the provided context, in that sense it's a rather poor answer, but arguably that's tangential. I'd tend to agree that this question does show reasonable context. If we take the context into account, likely it's a dupe. – quid Sep 23 at 15:52
• Instead of saying "what goes wrong with my thoughts" or "how can I go on with my original approach", OP explicitly stated that "Any help will be appreciated". And @Clement C. helped this user by directly giving an argument. Not a poor answer, and there have four people considering it good. This post is an extremely poor choice for deletion. – Jack Sep 23 at 15:58
• quid does make a fair point that an answer showing how OP could go on with the original approach may be more useful for the asker. One could add such an answer after this post is reopened. – Jack Sep 23 at 16:06
• Are you trying to make a point that because somebody collected 50k+ points by violating site policies and doing others homework for them, then that gives their opinion added weight somehow? I guess selling dung to horseflies is a lucrative business, but it does not make a good math site. – Jyrki Lahtonen Sep 30 at 4:56

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.

Please undelete this post: $$n^4 + 4^n$$ is a not a prime

OP clearly states context for his/her question:

This question appeared in the undergrad entrance exam of the Indian Statistical institute.

When $$n$$ is even the proof is simple. For $$𝑛=2𝑚+1$$ I am utterly stuck.

True that this is a duplicate of some previous posts, but duplicate can be useful. Moreover, it is not necessarily easy at all to identify this question as a duplicate:

• The useful searching engine Approach0 is NOT well known, neither it is mentioned on the page of help center of MSE.
• A quick search of the expression $$n^4+4^n$$ on the MSE searching box returns something irrelevant:
• If one posts this as a new question: the "similar questions" box does not show any one of the duplicate:

"Questions that are extremely off topic, or of very low quality, may be removed at the discretion of the community and moderators." This 5 upvoted one with three answers is not.

• At some point, every math student really ought to be shown the factorization of $x^4+4$. – Gerry Myerson Sep 26 at 7:47
• This is an umpteenth reincarnation. Even in 2013 when André Nicolas answered it we had already covered it many times. Also, while duplicates were seen as somewhat useful back in 2013 (when Jeff Atwood's strangedupe comment was often cited), the site has moved on since. The most recent word from above (don't remember for sure whether it is from JA or the current CEO Joel Spolsky) reads: Over time duplicates become vast landmine fields. – Jyrki Lahtonen Sep 26 at 16:24
• The sentence ("... landmine fields") Jyrki mentioned is from this article by Jeff Atwood. That one is specifically talk about StackOverflow, which is sort of the counterpart of MathOverflow. (cont.) – Jack Sep 26 at 17:18
• Jeff explicitly writes in that article the following : But I will point out that there is plenty of precedent on the Stack Exchange network for splitting sites into "expert" and "beginner" areas with slightly different rulesets. We've seen this for Math vs. MathOverflow, English vs. English Learners, Unix vs. Ubuntu... perhaps it's time for a more beginner focused Stack Overflow where duplicates are less frowned upon, and conversational rules are a bit more lenient? – Jack Sep 26 at 17:18
• I am not following SO much at all, but what little I have seen of it it is nowhere near the level of sophistication of MathOverflow (admittedly my observations are likely biased). But I would support walling off lower level math (like freshman and below) to a Math Learner site. – Jyrki Lahtonen Sep 26 at 21:49
• I don't get what's the contradiction even. Certainly duplicates will happen, some will be caught other won't be caught. Of those that do get caught we'll keep some that seems relevant as "sign posts" and we remove the rest without much ado (either way). Why would we want to keep them? – quid Sep 26 at 22:26
• On search, searching n^4 + 4^n for works like a charm Why would one use strange spacing, or in any case just check one version, and include the completely irrelevant dollars? – quid Sep 26 at 22:34
• @quid: your linked search of n^4 + 4^n , which does return a duplicate result, uses "strange spacing". If one searches n^4+4^n without the spacing before and after the plus sign, one would not see the charm. – Jack Sep 27 at 0:04
• The answers are all dupes of answers given many times in the past. This FAQ occurs many times every year. There is no need to keep adding duplicate answers every time it reoccurs. Doing so makes it difficult if not impossible for users to locate the most enlightening answers. – Bill Dubuque Sep 27 at 0:45
• @Jack I forgot to add that Theoretical Computer Science is the StackOverflow analogue of MathOverflow. Don't get mislead by the inclusion of the word Overflow. If SO walls off a learners' site, we should do the same. – Jyrki Lahtonen Sep 27 at 3:42
• And also, the voting already gives low level math an unhealthy advantage in the gamification aspects of the site. Simply because users are obviously not going to (and should not) vote on material over their head. You wanting to be more lenient about low level duplicates would exacerbate an already serious problem. – Jyrki Lahtonen Sep 27 at 3:45
• Well, let's forget about which spacing is strange or not. One might learn the lesson that one should search for both variations. I'd still maintain that the spacing there is the more natural way to type it. But I am glad that you seem to agree now that the dollars are useless. // And even if it was completely unnatural it is the very spacing that was used in that post that you want undel too. Thus at least that user likely would have used the same spacing if they had searched and keeping this as a dupe would not even help future searches (except maybe via answer, but then merge could do). – quid Sep 27 at 8:44

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.

Deleted, undeleted, deleted, undeleted, reopened, closed as duplicate

Please reopen Calculating the summation$$\sum_{n=1}^{\infty}\frac{H_{n+1}}{n(n+1)}$$ because it's not an elementary question and OP has tried checking the proposition using Wolfram Alpha.

• In my opinion it's very poor style to reignite this after month without mentioning any of the earlier activity in which you even were involved. Thus, I locked the post for now. – quid Apr 30 at 11:43
• I'm puzzled. A "content dispute" notice was lifted in March 2018. The content has not been altered since then. So it seems strange to lock it for "content dispute" now, @quid. [I guess I should mention that I was involved in earlier activity.] – Gerry Myerson Apr 30 at 13:56
• @GerryMyerson Are your really puzzled or are you just searching an argument? First, the content of the post was also not changed between the first locking and the first unlocking. Second, the lock was not lifted in the sense of somebody lifting it, it simply expired. It was not reinstated as there seemed no need back then about a year ago. Then half a year ago, there was one more round of undelete-delete but it fizzled out quickly. Now somebody wants to go back to this again, indeed without any further changes, simply picking up the del-undel again. To prevent this, I locked it. – quid Apr 30 at 14:36
• Third, it might be relevant to note that the lock was "lifted" while the post was deleted. Thus, if consistency is the concern of course I should lock it again now. I could also have it become undeleted and then personally delete it again. Last time around some where keen on locks being used. So, there you go. Of course that's not fine for you now either, presumably because it does not cater to your personal preferences. – quid Apr 30 at 14:43
• To sum up, I locked it to prevent the delete-undelete cycle being restarted. By now the question was deleted four times. Plus it is an odd situation, in that it first got siginificantly improved by a third party only for this then being undone If anything should happen likely a completely new version should be posted. This would be a reasonable thing to do if preserving content is the actual goal. Of course if playing un-del games should be the goal... thus locked. @GerryMyerson – quid Apr 30 at 14:48
• @quid, when I write that I am puzzled, please do me the courtesy of accepting that I really am puzzled. I'm puzzled not so much by the locking but by the phrase, "Content dispute", when there was no change in content. Had the locking notice said "Prevent delete/undelete cycle" I don't know that I would have made any comment. Does a moderator have the option of inserting custom-made locking notices, or is "Content dispute" the only phrase available? Also, I always assumed that when a moderator locked a question, the question stayed locked until a moderator decided it was time to unlock it.... – Gerry Myerson Apr 30 at 22:46
• ....I didn't know that locks expired of their own accord after a week. I've been here almost a decade, and I'm still learning how the place works. – Gerry Myerson Apr 30 at 22:47
• @GerryMyerson the list of reasons is fixed (we can ask for additions in principle but not spontaneously) "content dispute" is the one commonly used in this case, others are "off topic comments", "contest question", "cw answer", "historical significance". We can lock for an hour, for a day, for a week, or permanently. Usually one tries to avoid permanent locks. – quid Apr 30 at 23:58
• Probably it's worth mentioning that there already is one answer in this thread about the same question. – Martin Sleziak May 15 at 7:34
• @quid, thanks for the explanation about length of locks. It's not possible, is it, for non-moderators to see what length a moderator has chosen when that moderator locks a question? – Gerry Myerson May 20 at 4:26
• @GerryMyerson indeed I think that's not possible. – quid May 20 at 8:39

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. – Gerry Myerson Aug 30 at 0:06
• @GerryMyerson Correction made. Is there anything else? – Arbuja Aug 30 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. – Gerry Myerson Aug 30 at 2:32
• @GerryMyerson Users are trying to delete my post. Is this acceptable? – Arbuja Aug 30 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 at 21:40
• Or you could also start a bounty :) I think you can set one for +150 – user486983 Aug 30 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? – Gerry Myerson Aug 30 at 22:54

Reopened, undeleted, closed

Please consider undeleting this question where I also provided an answer: Integrating $$\int_0^1\frac{x\ln (1+x)}{1+x^2}dx$$ with restricted techniques.

The OP from clearly provides background on how the integral appeared, although it was some kind of homework now it can be useful for others too.

• It's good form to disclose that one has an answer on the post oneself. – quid Aug 15 at 20:59
• Hope I don't sound rude, but I don't understand what you wrote even with translate. Did you meant: It's a good thing to mention that I posted an answer to the linked question? – LeBlanc Aug 15 at 21:07
• Yes. You should mention this. It makes clear that you are not a neutral third party. You have a personal interest in the undeletion. This does not disqualify you from making the proposal. But it is good form to be upfront about it. – quid Aug 15 at 21:12

Deleted, undeleted, deleted, undeleted, deleted, undeleted, deleted, undeleted and reopened

unfortunately the question I asked Why is the zero polynomial the only one to have infinite roots? was put on hold as off-topic first and then closed. I edited it much for it to be reopened but it wasn't opened. I apologise if it was off-topic to you, but I edited it. If it being off topic yet, kindly suggest improvements or reopen it.

• Please include a link to the question. – quid Feb 3 at 14:54
• its humble request – user629353 Feb 3 at 14:56
• why you deleted that – user629353 Feb 3 at 14:58
• @quid couldn't you suggest edits – user629353 Feb 3 at 15:03
• "couldn't you suggest edits " What do you mean? How am I supposed to know which question you mean? – quid Feb 3 at 15:05
• @quid the link of which i have given above – user629353 Feb 3 at 15:09
• I misunderstood what you meant. I did not delete you question. At the moment I do not plan to get involved. – quid Feb 3 at 15:46
• Two posts here about the same question. Are we supposed to expect some more any time soon? – Did Feb 3 at 21:39
• @Did, the first post was about closure, the second, deletion. Unless there is some action more severe than deletion, I'd guess there won't be any more posts about the question. – Gerry Myerson Feb 3 at 21:52
• I have flagged the question on main to ask the moderators to let the community make the decision. – Gerry Myerson Feb 5 at 11:48
• The main problems with the question seem to be that (i) the questioner is confused, and (ii) it's tricky to answer in a way that properly addresses the confusion. The first seems a good reason to ask the question, and the second suggests that good answers will be thoroughly explanatory and therefore of high value. – timtfj Feb 5 at 16:05

The question Problem with sum of projections was incorrectly marked as a duplicate of Orthogonal projections with $\sum P_i =I$, proving that $i\ne j \Rightarrow P_{j}P_{i}=0$. The latter question has the additional hypothesis that the projections are self-adjoint (i.e., orthogonal projections) which allows for some rather different proof methods. Indeed, none of the four answers to the second question solve the first question.

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 Aug 28 at 12:31
• I posted a link to an exact duplicate under that thread. Pointless to reopen I think. – Jyrki Lahtonen Aug 28 at 18:59

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. – Gerry Myerson Jul 29 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. – mrtaurho Jul 30 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. – Gerry Myerson Aug 11 at 23:13
• @GerryMyerson Thank you, for your response. I will do so, as soon as I have time! :) – mrtaurho Aug 11 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. – Gerry Myerson Aug 27 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. – mrtaurho Aug 27 at 0:14

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.

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. – Gerry Myerson Aug 23 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. – Jack Aug 23 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 Aug 23 at 21:08
• @quid Why the account deleted is a 'point to count' to support the deletion? – user486983 Aug 23 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 Aug 23 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 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 Aug 23 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 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. – Martin Sleziak Aug 29 at 6:58

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.

Undeleted, reopened, closed as duplicate

Please consider undeleting this well-received (33 net upvotes) question under the tag of probability: Probability of drawing the Jack of Hearts?

There are useful discussion and several good answers, one of which has 77 upvotes.

• The question was originally closed as "off-topic: lacking context" (which, in my opinion, was not unreasonable). It is, however, also a duplicate of other questions, as indicated by the comments. If it is to remain on the site, it should be properly linked via a dupe closure. – Xander Henderson Aug 19 at 17:38
• At most "similar" or "related". Not a duplicate. – Jack Aug 19 at 17:54
• I'm sorry, but what? The question above asks us to determine the probability of drawing a Jack from a deck of cards from which an unknown card has been removed. One of the two questions in the dupe target asks for the probability of drawing an Ace from a deck of cards from which an unknown card has been removed. These are precisely the same question, and answers to the older question completely answer the newer question! How is this not a duplicate? – Xander Henderson Aug 19 at 18:32
• Mr. Henderson, I have a very narrow definition of "duplicate" from yours. No need to be sorry. And of course you do have the right to vote it as a duplicate. – Jack Aug 19 at 18:34
• I marked it as a dupe. That said @Xander I think the difference is slightly larger than you make it look. This question is about one specific card (a jack of hearts), while the dupe is about a group of cards (an ace). I still think that is a duplicate. // Since the comment on main got auto-deleted I'll add that two users other than me had mention it as a dupe. Thus, it was at least a trilateral closure. :-) – quid Aug 19 at 18:54
• @quid Indeed, I had missed that. That said, as you note, the distinction is not fundamental. Thank you for handling it. – Xander Henderson Aug 19 at 19:39

Reopened

Theorems with the greatest impact on group theory as a whole (note that the question is about infinite group theory).

It is currently closed as "primarily opinion-based...Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise."

I disagree with this close reason:

1. As the 11-upvoted comment states, "This is a good question and does not deserve to be closed. Understanding the theorems that are considered most important in any field of math is an important step towards understanding that field." The theory of infinite groups is an area of active research, and is not covered specifically in an undergraduate course on groups. In fact, many results covered in undergraduate group theory are not applicable to infinite groups (Sylow's theorems are a good example, and are mentioned in the question).

2. The boiler-plate reason is that "answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise". There are currently two answers; both are based on facts and references, and both are by professional mathematicians (one is by Andrés E. Caicedo and the other is by me, and indeed my research is in infinite group theory).

Finally, I want to end with a comment: The question is almost 6 years old (5 years and 355 days, or so). The close votes here seem to have occurred after a re-tag (which I presume happened after I linked to the question elsewhere). Closing reasonably-upvoted old questions like this has the potential to discourage improvements to old question and to discourage linking to old questions.

• re 3. The question had been closed back then already. – quid Aug 19 at 15:21
• I've edited 3 (it wasn't really a reason to reopen). Yes, it was closed and then it was reopened. – user1729 Aug 19 at 15:23
• So, the question was already controversial back then. Which is documented by the first comment at score +12. Don't create false narratives; – quid Aug 19 at 15:24
• @quid I don't see what was false about my narrative (or that I have written a narrative). My the purpose of the final paragraph (in both current and original form) was to point out the age of the question and what closing such old questions could mean. I did not mean to suggest that the question was not originally "controversial". – user1729 Aug 19 at 15:30
• Further, professional mathematician or not (what type of argument is that by the way?), one of the answers does not even seem to answer the question at all. // The (at least implied) narrative is that after years were this question was welcome suddenly people took issue with the question, which is incorrect or at least incomplete. To not even mention this is careless at best. – quid Aug 19 at 15:35
• People can (and should) look at the question and make up their own mind. I do not believe that it is my job here to give them all the relevant information (because what is relevant differs from person to person - for example, you focused on the close votes, but the question has only one downvote). Re "professional mathematician": my point was what I have the specific expertise to answer this question (and ignore the other answer if you wish). – user1729 Aug 19 at 15:50
• It might not be your job to give all the relevant information. But I do believe that integrity ought to dictate not to give a highly biased description of the situation. – quid Aug 19 at 15:57
• The above being said, I do not have a particular issue with the question itself. I'd say it still falls on the good side in the good subjective-bad subjective dichotomy, and the questioner had made an effort to steer clear of the pitfalls of the superlative. I cast the final vote to reopen. – quid Aug 19 at 16:12

Undeleted, deleted, undeleted, deleted, undeleted, reopened

Please consider casting the final undelete vote and reopening this post:
Evaluate $$1+2-3-4+5+6-7-8+\cdots+50.$$

This question is well written and with effort. It has very well written answers, one of which gives a generalization of the problem.

Undeleted, deleted, undeleted, reopened, closed as duplicate (mod)

Please consider undeleting this post: 2011 IMC Section A Problem 3

This is not an ongoing contest problem. The answer is known online. @Aqua's answer (with 14 net upvotes) is a useful one.

• Poorly explained answer. Had downvoted it back then. – quid Jul 6 at 19:53
• That was a really bad excuse for deletion. – Jack Jul 6 at 21:09
• Since I did not delete it, I don't need any excuse (and I doubt the delete-voters where aware of my voting back then). Please do not write comments that might suggest otherwise as not everybody can check it easily. – quid Jul 6 at 22:20

Undeleted, deleted, undeleted, locked and merged with duplicate (mod)

Please consider undeleting: How to count the number of good permutations?

This is not a duplicate and has a good answer.

Deleted, undeleted, deleted, undeleted, deleted, undeleted, reopened, closed as duplicate, deleted, undeleted

What OP wrote under the problem statement clearly show his/her thoughts:

How can I do this if I don't know how $$a_n$$ is defined? I can use the given limit to get the range of $$a_n$$ in terms of $$L$$, but I lack the direction to complete the proof.

This is not a zero effort question. Please consider undeleting this post:

Given positive sequence $$a_n$$ where $$\lim _{n\to \infty} a_n = L, L >0$$, prove that $$\lim_{n \to \infty} 1/a_n = 1/L$$

• Did you check if it's a duplicate? It's a very standard question. – quid Apr 26 at 14:32
• @GerryMyerson a question might be eligible for closure for multiple reasons. It's maybe not a PSQ in it's purest form, but it's still not a good question. I'd say if somebody wants to restore a question it's on them to make sure no reason applies not just the one that was chosen. Further, it would have been on the asker to make some good faith effort to find a dupe before answering (and then complaining that their answer was removed). If a dupe of this question is not findable what does this tell about the level of organization in those tags. The priorities are not good. – quid Apr 27 at 7:12
• @GerryMyerson here math.stackexchange.com/questions/1171733/… it was pretty trivial to find. – quid Apr 27 at 7:22
• Well, in any case they complain. We can replace the "that" by "after". On the rest, again the onus is on them. They ought to explain that there is no dupe (supposedly). Further, it is generally considered as good form to mention if one has answered oneself. Especially if it is the only answer. @GerryMyerson – quid Apr 27 at 7:26
• @GerryMyerson not sure about that. I might have had the luck to use the better strategy for that example, searching for words via Google on this site not for formulas for example 'convergence of inverse of convergent sequence' works well. – quid Apr 27 at 7:31
• @GerryMyerson (and quid) I did try to find a duplicate and I indeed noticed that limit of reciprocal of a sequence away from zero should be a rather standard exercise in calculus/analysis and should have been asked before. However, I think "context" counts as an integral part of a post, and that is why we insist on "contexts", don't we? [cont.] – Jack Apr 27 at 13:14
• [cont.] I am not able to find any same/similar confusion ("How can I do this if I don't know how $a_n$ is defined?") in any known post, for instance in the linked post in one of quid's previous comments and thus I do not think this post should be considered as an "absolute" duplicate that one should delete it. – Jack Apr 27 at 13:14
• I agree with Jack's comments above, I don't think this post should be closed if a duplicate is not found where the same confusion is addressed. To the best of my knowledge, this confusion has not been addressed before, so this post should be undeleted and reopened. – Brahadeesh Apr 28 at 5:43
• @GerryMyerson Basically a duplicate, except it doesn't require $a_n$ to be a positive sequence, was asked fairly recently at Sequence Limit Reciprocal Law Proof, where I provided an accepted answer. As for finding it, note it originally only used the tag "elementary-number-theory", but I changed it later to "limits", so searching for it initially might not have turned it up. However, I can't see the original deleted question content, but the page it brings up shows $2$ other somewhat related ... – John Omielan May 2 at 8:08
• (cont) questions: Given: $\lim\limits_{n\to\infty}a_n=0$ prove $\lim\limits_{n\to\infty}\frac{1}{a_n}=\infty$ and How to formally prove that if $\lim \limits_{n \to \infty}a_n=\infty$, then $\lim \limits_{n \to \infty}\frac{1}{a_n}=0$.. Although they're somewhat different, and I haven't checked them carefully, I suspect their techniques are transferable. – John Omielan May 2 at 8:09
• The status of the question had not changed at all. What is the justification for this edit? – quid May 31 at 16:57
• On the comments above, which I only see know, due to lack of a notification, that's not a particular confusion. Any generic proof will necessarily do just fine to address this. I mean the proof you gave is completely generic. What do you think you did to address whatever specific confusion? – quid May 31 at 17:04
• I agree with Brahadeesh's comment and I've undeleted the question. – GNUSupporter 8964民主女神 地下教會 Jun 14 at 9:21
• @quid The quoted question in Jack's last comment answers your first question; point (3) in Jack's answer addresses your second one. – GNUSupporter 8964民主女神 地下教會 Jun 16 at 3:17
• @GNU As detailed this ask nothing more than that the author understands that they might be able to do it or at least how to strat for a specific sequence like say $2n/(n+1)$. Any generic proof will do just fine, and what about the third point? Again any proof will have to address this somehow (in one based on continuity it might be hidden). Certainly it's findable in other answers. It's just a contrived argument to save this post, and frankly I am appalled by this. Explain how this answer math.stackexchange.com/a/1171755 is not sufficient or math.stackexchange.com/q/54754? – quid Jun 16 at 8:51

Reopened

Prove: there exists 3 sets: $A, B, C \subseteq \mathbb{N}$ such that: $A\cap B\cap C =\emptyset$ and $|A|=|B|=|C|=\aleph_0$?

Please consider reopening my question as I've edited it in order to explain the full context of it.

• The current status is only to be added after a change occurred. In any case it should always be the current status of the post not the requested action. – quid Aug 15 at 13:19
• I understand. thank you for the help – Jneven Aug 15 at 13:20

Undeleted, deleted, undeleted

Please consider undeleting this post: How to evaluate $$\lim_{x \to 3} (x^2-5x+4)^{x-3}$$, which is clearly not a zero-effort question.

• You say that the question should be opened because it is "clearly not a zero-effort question." This seems to imply that the question was closed because it "lacks effort". However, "lacks effort" is not one of the close reasons used on MSE. Indeed, I see that question was closed for "lacking context". For example, a description of what theory the asker is familiar with and what course they are taking. Are they expecting a computation involving $\varepsilon$s and $\delta$s? L'Hospital's rule? What? The question should be deleted. – Xander Henderson Aug 15 at 12:31
• Moreover, examining the comments attached to that question, it is not even clear where the function being discussed is meant to be defined. Is it a real function with a very "hole-y" domain? or a complex function, in which case one needs to consider branches of the logarithm? It is not a good question. – Xander Henderson Aug 15 at 12:34

Undeleted, deleted, undeleted

Please undelete and consider reopening this post: Show this equation has every positive integer as solutions

OP did give his thoughts. NOT a no-context question. And there are two good answers.

Undeleted, reopened, closed

How to find $${\large\int}_1^\infty\frac{1-x+\ln x}{x \left(1+x^2\right) \ln^2 x} \mathrm dx$$?

This is not a trivial exercise and OP shows his/her thoughts that "Routine textbook methods for this complicated integral fail." It has several very well-written detailed answers with rather high number of upvotes.

• '[S]hows his/her thoughts that "Routine textbook methods for this complicated integral fail."' That's not relevant context. Most likely it's a constructed challenge and should have been declared as such. This type of post borders on a misuse of the site. The following comment at score 13 is relevant I feel like it's becoming a trend to ask questions about practically impossible integrals. – quid Jul 8 at 19:34
• You think "That's not relevant context." And this proposal focus particularly on undeleting the post. Considering THREE high-quality answers (4+31+40 upvotes) that already existed I find it ridiculous (yes, this is my rant) to delete this OLD post. If there is any misuse of this site at all, the deletion, in this particular case, IS misuse of the privilege of votes. [mod redacted] – Jack Jul 8 at 19:58
• Bringing up other users in this form is out-of-line, in general. In the specific case it's also highly misleading. (I removed it.) – quid Jul 8 at 20:24

## protected by Community♦Oct 1 '18 at 14:49

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).