27 votes

Before MathOverflow

Before MathOverflow, the culture of mathematics question-and-answers was quite primitive. I remember the days when a student would impress their mathematics questions, expressed in cuneiform, by ...
20 votes

Requests for reopen and undelete votes for closed and deleted questions

[RE-OPENED and later CLOSED again] The question How the idea of adjoint matrix has been designed? isn't great, but isn't awful, and these two answers have been posted (and upvoted) on G+ rather than ...
17 votes
Accepted

Before MathOverflow

Usenet For example, these newsgroups: sci.math sci.math.research sci.math.num-analysis sci.math.symbolic See back in time to them HERE
  • 38.8k
12 votes

Examples of mathematical exposition arising from MO answers

This paper resulted from a question on mathoverflow. This monograph on properties of 3-manifold groups has now appeared in print.
  • 63.1k
11 votes

Interesting (and not sufficiently answered) questions on math.SE

Does the open mapping theorem imply the Baire category theorem? The open mapping theorem and the Baire category theorem are both theorems of ZFC, but are independent of ZF. Working in ZF, one can (...
11 votes

Interesting (and not sufficiently answered) questions on math.SE

Is there an injective cubic polynomial $\mathbb Z^2\rightarrow\mathbb Z$? This question asks exactly what its title suggests: is there a polynomial of degree $3$ in $\mathbb Z[x,y]$ whose induced map ...
9 votes

Interesting (and not sufficiently answered) questions on math.SE

Here is a question which seems interesting, What does it take to divide by $2$? In a nutshell, we know that in $\sf ZF$, assuming classical logic, we can prove that if $A\times\{0,1\}$ and $B\...
  • 36.6k
9 votes

Examples of mathematical exposition arising from MO answers

The note "Did a 1-dimensional magnet detect a 248-dimensional Lie algebra?" by David Borthwick and Skip Garibaldi mentioned in this MO answer by Garibaldi was published here in the Notices of the AMS.
  • 13.3k
9 votes

Examples of mathematical exposition arising from MO answers

My preprint arXiv:1609.01160 was written in response to Question 248665.
8 votes

Requests for reopen and undelete votes for closed and deleted questions

[RE-OPENED] I believe the post Can you write $\mathbb R^2$ as a disjoint union of two totally disconnected sets? has been closed (or put "on hold") erroneously, as a duplicate of Can you explicitly ...
8 votes

Before MathOverflow

IRC (Internet Relay Chat) had #math channels where people discussed concepts using an obscure dialect called ASCII. There were moderated and unmoderated forums with thread based email discussions ...
7 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] The question Has Perelman's proof been accepted or are there still unresolved issues? has been closed as of this writing. At first glance, this question seems to be of the genre, "Is ...
6 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] The OP of this question Connected sum is well-defined for surfaces, proof? requests reconsideration to reopen. It was closed as a duplicate, but OP says that what is asked for was not ...
6 votes

What MO is for and what is *your* aim in participation?

First let me say that these are very good questions. My answer to the second one would be similar to many others, let me just add that MO has immensely enhanced my feeling of being a member of one of ...
5 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] I'd like to suggest reopening Covering systems. As I wrote in a comment, Why is this closed? Covering systems are a recognized area of research in Number Theory. It's known that in an ...
5 votes

Requests for reopen and undelete votes for closed and deleted questions

The question A question on $p$-approximation property from 2014 has been automatically deleted owing to lack of upvotes. While I can't immediately tell if it is a good question, it seems a perfectly ...
5 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] Parameterizing rotations of a cube was asked and answered, but I don't see a reason for closing it.
5 votes

Requests for reopen and undelete votes for closed and deleted questions

[UNDELETED] This is an undelete request for an answer on meta: namely, quid's answer to my question Some proposals for modifications of the process of closing/reopening questions . The answer was ...
5 votes

Requests for reopen and undelete votes for closed and deleted questions

[RE-OPENED] I think that the question How does a mathematician choose on which problem to work? was too broad in its original formulation (beginning: "How does mathematical research work?") and so I ...
5 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] I'd like to nominate this question. It originally got closed due to a typo, which has been fixed. It's certainly not "unclear what you are asking" any more (the original reason for closing)...
5 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] The question Center of a monoid ring asks two questions, one of which can be found in standard texts and the other which is essentially an open question but which appears to be a harmless ...
5 votes

Interesting (and not sufficiently answered) questions on math.SE

Weil Pairing on Linear Algebraic Groups There is of course a Weil pairing on abelian varieties (it pairs an element of the torsion with something in the torsion of the dual) which are projective ...
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5 votes

Interesting (and not sufficiently answered) questions on math.SE

Another user suggested that I should advertise this question in MO also, so here comes. It is just a number theoretic curiosity spawned by an earlier question where small cases were handled by a ...
4 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] This question was heavily downvoted and closed: When a compact topological manifold with boundary is a ball? Color me ignorant, perhaps, but I wondered if it were as trivial as the ...
4 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] The question Lexicographic order on increasing $k$-tuples by a first-time poster was closed as "unclear what you're asking". I have rewritten it so that (I think) it is now clear. It is ...
4 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] "Find a TSP tour passing through at least one node in each set of nodes" was initially unclear, but the author has now clarified it into a real question (and I corrected the English): Is ...
4 votes

Requests for reopen and undelete votes for closed and deleted questions

[REOPENED] The question Identify one group of linear transformations was closed as "unclear what you're asking". Afterwards it has been edited and clarified. I don't see what is still "unclear" in ...
4 votes

Requests for reopen and undelete votes for closed and deleted questions

[UNDELETED] [REOPENED] [CLOSED] I would suggest to undelete/reopen https://mathoverflow.net/q/328312, as a courtesy and sign of respect, and then hopefully one of our experts can answer it. I know, ...
4 votes

Requests for reopen and undelete votes for closed and deleted questions

Status: [REOPENED] Thank you! Request to reopen How to obtain the rational solution of a linear system efficiently?. In light of recent discussions about being more welcoming to good faith questions ...
4 votes

Requests for reopen and undelete votes for closed and deleted questions

https://mathoverflow.net/questions/379145/geometric-combinatorial-problem-in-the-euclidean-space This question was deleted by nobody less than @ToddTrimble just 10 days ago after having 9 upvotes and ...

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