# Requests for reopen and undelete votes for on-hold, closed, and deleted questions

Since I expect this may prove rather useful, I'm blatantly purloining Asaf's question from meta.math.se.

Beware that "short" requests such as "request reopening of <link>" may be automatically converted to comments by the SE software, so you will need to say more, such as why you think that the question should be reopened.

Please do not use this thread to engage in debates on contentious matters (e.g. reasons for closure). That should be done in a separate thread - which can be linked to from here.

If a question is reopened then please put [REOPENED] at the start of the request (answer).

Of course, each requested question may need some editing or other improvements before it is fit, and as indicated elsewhere, this is desirable, and I hope may be expedited through this thread.

(Improvements on the phrasing are welcome.)

• Not entirely necessary. There's a reopen queue now. A closed post can be put into the reopen queue by editing or voting to reopen. 3k+ users can vote to reopen (or alternatively vote against it). If this mechanism fails, then one can open a separate meta post about the question. I find that this is a more efficient process :) – Manishearth Jun 27 '13 at 21:10
• @Manishearth: Not everyone has access to the queue history, so not everyone can tell when a thread has been "outlived its review" and it is time to come to meta. In the long run, I think it's better to have one post for "run of the mill reopen votes" rather than having more and more separated questions whose answers would consist mostly of "Done." – Asaf Karagila Jun 27 '13 at 22:06
• @AsafKaragila Yeah, I see your point -- but "outlived its review" can just mean "wait a day", regardless of its queue status. So, if a reopen vote or edit doesn't push it out of the queue in a day, then come to meta (and post on this post, or separately -- IMO separate meta posts lead to better discussion, but that's just me). But if you take a look at the MSE post: Most of the recent ones are either obvious nos (closed post) user whinging about closed post, or obvious yes's (Awesome edit improved post). – Manishearth Jun 27 '13 at 22:31
• These can be dealt with fairly within the review queue itself; giving an explicit platform on meta for people to whinge or where people feel obliged to post obvious reopens is imo unnecessary. Again, I don't know much about MO or MSE, so I could be grossly wrong here :). Just giving an outsider's viewpoint. – Manishearth Jun 27 '13 at 22:32
• I agree with Manishearth: with the new "on-hold" -> edit -> add to re-open review queue mechanism, threads like this should be much less necessary. – Willie Wong Jun 28 '13 at 9:21
• @AsafKaragila Btw, this is why doing it separately is imo better, you get a lot more feedback and discussion. – Manishearth Jun 28 '13 at 16:59
• I dont want to interfere here with anything but I disagree with Manishearth about the usefulness of this Request to Reopen List. At Math SE I have observed that it works very well and efficiently to get questions reopend without making much fuzz about it. At Physics SE, we controversely discuss each question that somebody thinks should get reopend at meta seperately at length with the effect that people just discuss instead of just doing it, and almost nothing gets reopend at the end. – Dilaton Jul 3 '13 at 17:44
• Reopening questions the way people at Math SE do, has in my opinion the additional advantage that people who have less than 3000 rep and therefore not yeat access to the Reopen queue can take part in the reopen process by upvoting the answers of this post, which makes reopening of questions that deserve it more efficient. – Dilaton Jul 3 '13 at 17:54
• People are now misusing this post in order to find questions related to the closed/deleted questions to downvote and close. – Joseph Van Name Apr 17 '19 at 3:13

[REOPENED]

I would like to request to reopen Relation between the Hochschild cohomology of group algebras and groupoids. The original question was very vague, but it has since been edited and is now, in my opinion, a perfectly fine question.

Re-opened and then re-closed

I don't think it is obvious how to find the shortest chord that bisects the area of a convex polygon. That is the question posed in this now closed post: Shortest bisecting line. Perhaps one would have to use the algorithm below, modified to spin the direction through $$180^\circ$$.

Shermer, Thomas C. "A linear algorithm for bisecting a polygon." Information Processing Letters 41, no. 3 (1992): 135-140.

The question Why do some mathematicians believe that the notation $$(x_n)_{n\in \omega}$$ is better than $$(x_n)_{n=0}^\infty$$ or $$(x_n)_{n\in \mathbb N}$$ seems to be asked in good faith, even if the tone may have annoyed people who use the notation. It was closed as "primarily opinion-based" but I think that actual practitioners, especially those who work with the von Neumann model/definition of the ordinals, could have sensible answers from which we might all learn something.

I don't use this notation myself, but I have a joint paper where at least one of the co-authors does use this notation.

I think the question deserves to be re-opened and taken seriously.

• Maybe part of the reason for closure is that the question has been asked anonymously, by a user-xyz. – Stefan Kohl Oct 24 '18 at 23:21
• @jeq this is a tangent, but I don't think the inference "So Occam's Razor tells us that this unregistered user is already a known contributor to Math Overflow" is justified. Plenty of people who are English-speaking academics may have been aware of MO but not actually contributed before asking – Yemon Choi Nov 1 '18 at 23:40
• "deleted by Community♦ yesterday (RemoveAbandonedClosed)" so if it gets undeleted, it will just be redeleted unless it gets some upvotes and/or gets reopened and gets some upvoted answers. – Gerry Myerson Nov 4 '18 at 21:38
• @GerryMyerson Thanks for the reminder. If you look at the question it had a lot of early negative votes but also then some later upvotes – Yemon Choi Nov 4 '18 at 21:57
• At the moment, users below 10k still can see some version of the post in the Google Cache. (However, 10k+ users can check that some votes and comments cam after that version. If I understand correctly how Google Cache works, this version will be no longer be shown after Google crawls that page the next time .) – Martin Sleziak Nov 4 '18 at 23:45
• It seems that the question was posted from an unregistered account and the user what not online since the day they posted the question here, it's not clear whether they are still interested in this. This is probably for a longer discussion, but perhaps a possible alternative would be if somebody else posts a new question; with a link to deleted one - to give credit; and also with a more detailed explanation why the question is interesting - to prevent closure. – Martin Sleziak Nov 4 '18 at 23:52
• I am pretty sure that the question will be treated differently if it is not posted by a new user. (Or I could suggest posting on Mathematics - but I know that Yemon Choi does not have an account there, so in this specific instance it is a less optimal choice.) – Martin Sleziak Nov 4 '18 at 23:53
• It doesn't look deleted to me. Odd. – David Roberts Nov 5 '18 at 1:55
• @DavidRoberts well, someone or something has reopened it at some point between my edit and your comment :) – Yemon Choi Nov 5 '18 at 3:10
• (It's been undeleted but not reopened.) – Joel Reyes Noche Nov 5 '18 at 3:18

[REOPENED]

How slowly can it takes for the Fibonacci terms in a partially permutative self-distributive algebra to stabilize?

How slowly can it takes for the Fibonacci terms in a partially permutative self-distributive algebra to stabilize?

If $$(X,*)$$ satisfies the self-distributivity law $$x*(y*z)=(x*y)*(x*z)$$, then define an action of the positive braid monoid $$B_{n}^{+}$$ on $$X^{n}$$ by letting $$(x_{1},\dots,x_{n})\cdot \sigma_{i}=(x_{1},\dots,x_{i-1},x_{i}*x_{i+1},x_{i},x_{i+2},\dots,x_{n}).$$ Then $$(X,*)$$ is partially permutative if for each pair $$x,y\in X$$, there is some $$n$$ where $$(x,y)\cdot\sigma_{1}^{n}=(x,y)\cdot\sigma_{1}^{n+2},(x,y)\cdot\sigma_{1}^{n+1}=(x,y)\cdot\sigma_{1}^{n+3}$$ and if $$(x,y)\cdot\sigma_{1}^{n}=(r,s)$$, then $$(x,y)\cdot\sigma_{1}^{n+1}=(s,r)$$.

The motivation behind partially permutative self-distributive algebras is that the quotient algebras of elementary embeddings $$\mathcal{E}_{\lambda}/\equiv^{\gamma}$$ are always partially permutative (and much more) and because the action of $$B_{n}^{+}$$ on $$X^{n}$$ is simplified whenever $$(X,*)$$ is partially permutative.

I asked this question since I wonder how long it will take for the sequence $$((x,y)\cdot\sigma_{1}^{n})_{n\in\omega}$$ to stabilize if we know the cardinality of $$X$$.

Under large cardinal assumptions, we know that for all $$N$$, there is a finite partially permutative algebra $$(X,*)$$ and $$x,y\in X$$ where $$((x,y)\cdot\sigma_{1}^{n})_{n\in\omega}$$ takes more than $$N$$ steps to stabilize, but I do not know if one can remove the large cardinal hypotheses from this result.

[UNDELETED]

I would like to add as undelete-request On variants of the abc conjecture in terms of Lehmer means that was automatically deleted yesterday. If possible, I think that it is an interesting question about the abc conjecture. Many thanks.

• I note that you haven't enacted any of my suggestions for making the question more attractive to other users. – Gerry Myerson Mar 1 at 4:26
• I don't know if you've read my comment adressed to you (in the Meta post now deleted), that I can not edit my question since it is deleted. When I thy to edit the post, this message is communicated "This post has been deleted - no more edits are allowed." Many thanks in any case @GerryMyerson and good weekend – user142929 Mar 1 at 8:13
• @user142929 That seems some a bug which was also reported here: “This post has been deleted - no more edits are allowed” when editing own Roomba'd question. (Some possible workarounds are mentioned there, but it would definitely be better if the bug was fixed.) – Martin Sleziak Mar 1 at 8:25
• Mnay thanks @MartinSleziak – user142929 Mar 1 at 8:31
• Sorry, I missed your comment on meta.mathoverflow.net/questions/4462/… (and why did you delete that question?). – Gerry Myerson Mar 1 at 8:56
• You do not have to apologize about you missed the comment. I' ve deleted my Meta post since I want to solve my problem: which is about of a question that I consider interesting and important was automatically deleted @GerryMyerson . I don't know if ask a post for a discussion in Meta of these sites is useful, let's say that I've lost part of my hope in the discussions of the Meta of these sites, and that the first thing is solve my problem. – user142929 Mar 1 at 9:12
• Now it's undeleted, you should be able to edit your post. – YCor Mar 1 at 17:01
• Many thanks/Muchas gracias I've edited it while it was deleted, I can't make more substantial improvements following the professor's advices (see previous linked Meta, my previous recently deleted post in Meta) in this post, similar that those that I edited while it was deleted, but my purpose is to moderate/modulate myself posts following the advices, in particular I will try show my effort and more motivation in next posts @YCor . Sure that my post is interesting and after this stumbling block we can solve it – user142929 Mar 1 at 18:34
• If the question doesn't attract some upvotes and/or answers, presumably it will be auto-deleted again. – Gerry Myerson Mar 3 at 4:34
• Many thanks for the information, someone upvote it, and I hope that some user do some attempt to solve it. My motivation is my feeling that can be an interesting post: I would not have insisted if the deleted post had been another of my posts (other unanswered post that maybe isn't interesting). Many thanks again to you and professors that vote undeleted the question @GerryMyerson – user142929 Mar 3 at 11:12

Status [UNDELETED] . (Thank you!)

I ask that Counting multiples in short intervals be recovered. I will provide an answer that is an enhancement of Lucia's comment as well as motivation for the question. It is part of my exploration of a combinatorial approach in number theory. (GRP20200411)

• "be recovered"? – Gerry Myerson Apr 11 at 22:59
• If it were voted into deletion by members, I might say undeleted. Instead, an algorithm determined it be deleted, and I want it recovered. Thank you for interest and help. Gerhard "Now To Take Some Steps" Paseman, 2020.04.11. – Gerhard Paseman Apr 11 at 23:19
• OK, well, it seems to be there now. – Gerry Myerson Apr 11 at 23:30

[REOPENED]

An integral representation of the Riemann zeta function was closed, with commenters asking for more information. Author has now supplied the requested information. Perhaps the question should be reopened.

[REOPENED]

I request to reopen my question

Different Metrics for Baire Space and their induced Topologies

At first I had some flaws in the definition which I corrected by several edits and reedits, which made my post meandering. Now I totally rephrased the question and wrote it new. Also maybe I could delete the comment on my first definitions which are out of context now.

[REOPENED]

The question Square of primary ideals was originally closed as being "unclear what you're asking", but after the edit I don't think this is a valid reason anymore. (I'm no expert here, but it seems like a reasonable question to me.)

[REOPENED]

This question about Zariski topology is interesting, relevant but unclear, and it attracted two excellent answers. The question is ambigious and unclear because the situation is genuinly unclear to the OP who is a professional mathematician trying to explore a topic. It is unclear in a way where it is possible to understand what the author is thinking, and give useful answers for him and for others.

• Why do you expect the OP to be a professional mathematician? Also, he has been asked a quite specific question in the comments which might clarify what he means. Without an answer to that question I do not feel there is any good reason to reopen the question. – Tobias Kildetoft Apr 21 '14 at 6:36
• In an effort to understand how people use this thread, and think it should be used, with an eye towards improving our procedures, I would like to know if you: a. did not know of meta.mathoverflow.net/questions/1650/… or b. did know of it but still posted here. – user9072 Apr 21 '14 at 11:18
• Hi Quid, My post follows Frank Thorne's question (using similar wordings) and Todd's remark that mentioned this thread. I agree with Todd that the question is unclear (and not merely "slightly ambigious") but I think that the question reflects an issue which can be unclear to researchers in mathematics, and is thus research-level and should be welcome on MO. Of course, an endorsement to open not coming from the OP himself carries additional weight and I also want to endorse a policy of allowing umbigious questions of the kind a working mathematician occasionally have. – Gil Kalai Apr 21 '14 at 16:12
• Gil, I think such a policy is contrary to the goals of MathOverflow. I think you should endorse a policy of encouraging a questioner to participate in improving their question. This policy might mean a 48-hour hold before a "soft-" close of a question, but to have a new user ask something that needs improvement and does not respond to requests for that improvement is a situation that does not bode well for the forum. Better to make a temporary edit on the new person's behalf, or close the question. Gerhard "Or Start A New Question" Paseman, 2014.04.21 – Gerhard Paseman Apr 21 '14 at 17:07
• Right Gerhard, I certainly demand that the OP will make all possible effort to make his question clear before posing a vague question. But sometimes we encounter in our research/study questions which are (or seem to be) inherently vague. – Gil Kalai Apr 21 '14 at 17:19
• Thank you for the detailed reply! To avoid all risk of misunderstanding, let me stress again that my question was not meant as indirect criticism of you posting here. As the thread exists, it is a reasonable usage of it. – user9072 Apr 21 '14 at 19:32
• Gil, it seems we are in general agreement. When (the community of) MathOverflow is robust enough to handle such questions, then a more lenient policy can be adopted. I think the current success is due to the fact that almost all of the unclosed questions are focused, ask for specific things, and require little or no discussion as to meaning (after the formulation has stabilized). I think overestimating the robustness of the community is a real danger: supplementing vague questions with answerable portions may be a solution. Gerhard "Wants Success Without A Doubt" Paseman, 2014.04.21 – Gerhard Paseman Apr 21 '14 at 20:20
• I agree with Tobias. Referring to the OP as a "professional mathematician" is unwarranted and gilds the lily. The form of the question leaves little doubt that the OP is a student ("recently studied algebra", etc.), and OP still hasn't bothered to clarify the question, and I still disagree with "it is unclear in a way where it is possible to understand what the author is thinking" -- one can only guess what he/she is thinking. Why this question is being given a pass is simply beyond me. – Todd Trimble Apr 22 '14 at 16:32
• My confusion guys, I thought that Frank Thorne is the OP. Sorry! – Gil Kalai Apr 22 '14 at 17:34
• I agree with Todd Trimble on this. When a question is closed as unclear, and this one is admittedly so, then it makes sense to edit and clarify it before reopening (which may well be warranted here). I am a little surprised that no one has bothered to edit this question, and yet it has been reopened. – Lucia Apr 22 '14 at 17:53
• Silly mistake! Sorry again, but at least I learned the expression "gilds the lily. :) – Gil Kalai Apr 22 '14 at 18:08

[REOPENED]

(Edit: Since no one responded to the question of whether the closure reason is still valid, I took it upon myself to ask Joel David Hamkins, who discerns a clear and interesting interpretation and has expressed interest in answering, provided that the question remains open long enough. Therefore I cast a fourth vote to reopen.)

The post Can there be ordinals larger than those contained in Ord, and if so, can they be used to extend the constructible universe $L$? is currently on hold as "unclear what you're asking", but now that the question has been substantially edited, one user has flagged that this reason for on-hold no longer applies. If it is still unclear, then perhaps someone can say why, else I request a reopening.

• What I want to know is, why, when you ask people who wish to close a question to state their concerns, they don't? In the case of Noah S (as you can see from our conversation in the Comments), I was willing to address his concerns and would have been willing to address theirs as well. – Thomas Benjamin Dec 9 '14 at 16:15
• @ThomasBenjamin Yes, that would be nice. Three of the closers have professional interests in this area and could probably articulate such concerns, if they still apply (I think Noah S does too, but he was not one of the closers). Some people vote to close because they see no reason to disagree with other closers, as expressed here: meta.mathoverflow.net/questions/1954/… -- based on that stance, I wouldn't expect them to state their concerns. – Todd Trimble Dec 9 '14 at 20:08

[REOPENED]

Combinatorial puzzles involving half-integers

I believe it was put on-hold because of my inadequate definition of what I previously termed "guide lines". I fixed this. The only potential ambiguity left is my definition of "cells".

Moreover, the question garnered two upvotes in a very short period of time, so I feel reopening it is fair.

• The statement of the question does seem clear now; this means the "unclear what you're asking" no longer applies. The consideration then becomes whether it is considered on-topic for MO. – Todd Trimble Dec 29 '14 at 14:07
• So, Todd, do we reopen and then discuss whether it's on-topic? or do we decide whether it's on-topic, and, if it is, then reopen? – Gerry Myerson Dec 29 '14 at 18:40
• I think we only reopen it if we decide that it is on-topic. – Andy Putman Dec 29 '14 at 18:48
• @GerryMyerson What Andy said. Of course, people can decide on their own without there being a particular discussion. – Todd Trimble Dec 29 '14 at 18:50

The question

Mathematics of Computer science and AI

has recently been edited by someone after the OP in an effort to improve it, or make it more focused. I am ambivalent as to whether it should be reopened but I thought it deserved explicit mention/discussion on meta.MO

Mathematicians who were late learners?-list

Reason: How is this no longer relevant or specific to a certain geographical area or time? It is a valid history question. That can't be specific to a certain geographical area or time. I think this is a very interesting question; likely to help, or at least interest other users. Therefore think it makes no sense for this question to be closed, so I request it to be reopened.

[REOPENED]

I'd like to reopen When does $\nabla\times(\nabla\times F)=0$ imply $\nabla \times F=0$ . It is a clearly stated question, and seems like it has some interesting connections to differential topology.

[REOPENED]

{as of Mon Apr 11 15:03:06 UTC 2016}

The CW question Examples of math hoaxes/interesting jokes published on April Fool's day? was posted on 2016-04-01.

It has score of 69, 43 favorites and was answered by moderator.

I think it is too young to die and probably will edit, suggesting not to promote it to active on purpose.

[REOPENED]

I feel that the decision about closing my question:

was arbitrary. I hope that it will be reopened.

[UNDELETED]

which was auto-deleted due to lack of activity or votes, seems reasonable to me. But I am not a probabilist; comments from those who are would be welcome

• It's in danger of getting auto-deleted again, if it doesn't get some upvotes – isn't that right? – Gerry Myerson Mar 16 '17 at 3:47
• @GerryMyerson I think one upvote is sufficient, but I'm not sure – Yemon Choi Mar 16 '17 at 13:21

[REOPENED]

Graduate-level reference on temporal point processes seems like a perfectly reasonable / . The topic is research level but could be introduced in an advanced graduate text or monograph.

[REOPENED]

I originally voted to close this question. I've since reconsidered, and I've voted to reopen.

Basically, there are easy counterexamples for infinitely generated modules, slightly more sophisticated counterexamples for finitely generated but not finitely presented modules, and a positive answer for finitely presented modules. In comments, knowledgeable people have made false claims, so I think it's probably close enough to "research level" to reopen.

[UNDELETED and then REOPENED]

seems to have been closed over-hastily. Those with sufficient rep can see fedja's comments, and I am prepared to believe quite readily that if fedja thinks it is non-trivial, it is non-trivial.

I would like to nominate this for re-opening.

• How does this work – can a deleted question be reopened without first being undeleted? or does reopening automatically accomplish undeleting? – Gerry Myerson Jul 28 '17 at 4:57

[REOPENED]

A game-theoretical question in a political economy model is a well-written math question coming from research in a field outside of mathematics. It may well be easy but I think overall it would be worthwhile to reward the author with an answer.

• You're right -- the question is vastly improved from its initial formulation. I voted to reopen. – Lucia Sep 21 '17 at 23:00
• Looking at the timeline I see that this question went through the reopen review with 3 votes to leave closed. However, it seems that some of the edits were made after the reviewers' votes. (Probably the OP is unaware that it is the first edit that pushes the question into the reopen review queue. Although I am not sure whether it made much difference in this specific case.) – Martin Sleziak Sep 22 '17 at 9:58

[Undeleted]

Could I request that Question 290941, "Is the Normal centralizer problem in P?" be undeleted? It is a sensible question, and I spent some time finding a reference for the answer. It was then deleted by the poster - I have no idea why.

[UNDELETED AND REOPENED]

Can finite binary self-distributive algebras fit into small $n$-ary self-distributive algebras?

Can finite binary self-distributive algebras fit into small n -ary self-distributive algebras?

This question was deleted because it got no upvotes. A possible reason that the question did not get any upvotes is that it necessarily requires $$n$$-ary fundamental operations for $$n>2$$ and mathematicians typically do not work with ternary or $$n$$-ary fundamental operations See this question for possible explanations and for a discussion of ternary operations. Another possible reason it did not gain any upvotes is that the notion of $$n$$-ary self-distributivity has barely been studied.

Here are some reasons why the question and notions behind the question are reasonable.

1. The notion of $$n$$-ary self-distributivity generalizes the notion of an “inner endomorphism” to a more general context. I have encountered $$n$$-ary self-distributivity in my encounters with ternary and $$n$$-ary Laver tables (ternary Laver tables are really cool).

2. While the notion of $$n$$-ary self-distributivity may seem a bit difficult to investigate, the hull of an $$n$$-ary self-distributive algebra allows one to use binary self-distributivity to study $$n$$-ary self-distributivity. Since binary self-distributivity is easier to grapple with than $$n$$-ary self-distributivity, one should always take the hull of an $$n$$-ary self-distributive algebra.

3. This question is one of the more basic questions one can ask about the hull of $$n$$-ary self-distributive algebras and about the nature of $$n$$-ary self-distributivity.

• Now, someone has cast an unexplained and unjustified downvote against this question. I have been getting many such unjustified downvotes for some time now. – Joseph Van Name Mar 31 '19 at 2:44
• Now that I think about it, a 50 point bounty would have probably prevented such a question from being deleted in the first place. – Joseph Van Name Apr 17 '19 at 0:26

[UN DELETED AND REOPENED]

Is the variety of ternary self-distributive algebras generated by its finite members?

Is the variety of ternary self-distributive algebras generated by its finite members?

To convince you that this is a good question, let me explain a little about the mathematics behind this question.

Richard Laver has constructed a sequence $$(A_{n})_{n\in\omega}$$ of finite self-distributive algebras (which I now call the classical Laver tables), and he has shown under the existence of very large cardinals that the free self-distributive algebra on one generator embeds into $$\varprojlim_{n\in\omega}A_{n}$$. In particular, the free self-distributive algebra on one generator is contained in the variety generated by the classical Laver tables.

So I have extended the notion of the classical Laver table to a wide class of structures including the multigenic Laver tables. Furthermore, I have shown under strong large cardinal hypotheses that the free self-distributive algebra on countably many generators embeds into an inverse limit of multigenic Laver tables (the multigenic Laver tables are like the classical Laver tables but with multiple generators). In particular, the multigenic Laver tables generate the variety of all self-distributive algebras.

Now, the notion of self-distributivity can be generalized to $$n$$-ary self-distributivity and these generalized notions of self-distributivity give one an abstract notion of what it means for an algebraic structure to have “inner endomorphisms.” The notion of a Laver table can also be generalized to the notion of a ternary and $$n$$-ary Laver table. The only problem is that while the classical and multigenic Laver tables are always locally finite, the ternary Laver tables are in general not locally finite. The variety of ternary self-distributive algebras is probably generated by the ternary Laver tables, but since the ternary Laver tables are not locally finite, it is hard for me to predict whether the variety of self-distributive algebras is generated by its finite members.

[DELETED, Undeleted]

Reversible varieties

In this question I asked about reversible varieties, and it seems like the question has been deleted unfairly. The question has 2 unexplained and unjustified downvotes and only 1 upvote, so it automatically got deleted. I do not believe that these downvotes have any legitimacy since I have recently been receiving many downvotes and all of these downvotes for the questions that I have asked are without any explanation.

In this question, I proposed the notion of a reversible variety since I noticed that several varieties including the varieties of groups, racks, quandles, and other varieties have a flavor of reversibility in the sense that the fundamental operations are simply projections of bijective functions which are composed of these fundamental operations. I think of the notion of a reversible variety as being a generalization of the notion of a group. I therefore wanted to know if this notion has been investigated before in the concept of universal algebra, and I also want to see more interesting examples of reversible varieties.

This question so far does not have much to do with reversible computation, and the motivation for this question did not arise from reversible computation.

Incidentally, this follow-up question (Is this condition sufficient for a variety to be reversible?) which is also about reversible varieties has not been downvoted nor upvoted (and hence not yet deleted).

• People are misusing meta in order to cast more unjustified downvotes to questions related to the deleted questions. – Joseph Van Name Apr 17 '19 at 2:55
• Is there any reason why this post has a downvote? – Joseph Van Name Apr 17 '19 at 3:46
• The MO community has recently made it exceedingly clear that they do not want me on this site. – Joseph Van Name Apr 17 '19 at 3:52
• I see one downvote. ONE! A downvote doesn't mean someone doesn't want you here. I know you're not interested in my advice, but youtube.com/watch?v=SJUhlRoBL8M – Gerry Myerson Apr 17 '19 at 8:56
• Oh, and, for the 17th time, if you feel you're being targeted with downvotes, please, please flag for moderator attention. Complaining here is pointless, as only a moderator can do anything about such a situation. – Gerry Myerson Apr 17 '19 at 9:02
• Question has been undeleted BUT unless it sees some action (answers, upvotes) it will sooner or later be robo-deleted again. – Gerry Myerson Apr 17 '19 at 9:07
• I have been flagging these sorts of posts for unjustified downvotes. In my recent experience, such flags have been declined. – Joseph Van Name Apr 19 '19 at 23:50

[REOPENED]

The closure of this question seems rather rude to me, in particular in view of the strong gender bias on this site. -- Also I think neither its vote score nor that of its five upvoted answers supports the claim that it is considered off-topic on this site. Therefore I suggest to reopen that question.

• Note that the vote scores have been inflated by the fact that the question became a HNQ, so they do not necessarily reflect opinions of regular participants of MO. – Emil Jeřábek Jul 11 '19 at 14:31
• Also, it is off topic, as its connection to mathematics is by circumstance, not design. If it were happening in a different field, say biologists venturing into mathematics, I don't think it would stand at all as on topic for this forum. I am willing to consider it an exception to the rules and leave it for inclusion. Its popularity does not make it on topic. Gerhard "Will Not Vote To Delete" Paseman, 2019.07.11. – Gerhard Paseman Jul 11 '19 at 16:11
• FWIW I have cast a 5th vote to reopen – Yemon Choi Jul 13 '19 at 6:54

[No response from the OP, so I will leave this lie. I'm not that keen that I'm going to chase it up]

The question How to sort differential equation list? seems to me to be not uninteresting. The original asked about how to sort a list of DEs in Maple, but it's not really the Maple content that the asker is interested in, but rather if there is some reasonable ordering on (a class of) differential equations such that given a collection of them one could sort it into a list, so as to compare with other resources like OEIS.

It still very badly worded, but the above is what I think the OP wanted to ask.

• I'd rather see OP rewrite the question so it's actually comprehensible. Perhaps by explaining it to someone who is fluent in Emglish, math, and whatever language is native for OP. – Gerry Myerson Jul 20 '19 at 12:20
• Yes, I agree. This is more of a preliminary notice. I was going to encourage the OP to explain it more clearly. – David Roberts Jul 20 '19 at 23:37
• Given the terrible language, it’s not even clear to me if the question is really about differential equations, or if it’s just a mangled form of different. – Emil Jeřábek Jul 21 '19 at 8:40

I'd like to know why my question Looking for a conference about renormalization group methods has been closed.

As I said in the comments, there are other similar question such as the one that asking about Conferences about homotopy theory, one looking for Mathematical conferences in general, were rather positively received and allowed to attract nice answers.

Is there anything I can do to get it reopend? Maybe it should be CW?

• You are comparing to questions that were asked more than 3 years ago. The sort of soft questions people like has changed. – Tobias Kildetoft Nov 11 '13 at 20:15
• Another issue here is that this question is much narrower than the ones you listed, which were likely to be of interest to large groups of mathematicians. – Andy Putman Nov 11 '13 at 21:12

[REOPENED]

Mathematical explenation for why warm water freezes faster than cold water. Mathematical study of Mpemba effect? is a good question in applied mathematics and I propose to open it.