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 ...

Community wiki

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

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.

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

### 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.

9
votes

### Examples of mathematical exposition arising from MO answers

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

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 ...

Community wiki

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 ...

Community wiki

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 ...

6
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 ...

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 ...

Community wiki

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.

Community wiki

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 ...

Community wiki

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 ...

Community wiki

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 ...

Community wiki

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 ...

Community wiki

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 ...

Community wiki

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, ...

Community wiki

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 ...

Community wiki

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 ...

Community wiki

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 ...

Community wiki

4
votes

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

I use it to find out what questions people find interesting in order to gear my studies towards them. I search around for questions in things I am interested in and if no one is answering these ...

4
votes

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

Would someone who knows cyclotomic fields, or algebraic number theory more generally, please take a look at $A_4$ extension of $\mathbb{Q}$ ramified at one prime? The question asserts that an $A_4$ ...

4
votes

### Before MathOverflow

The Categories mailing list has been already mentioned in comments, I just want to add one detail, I think a significant one.
Mac Lane almost never posted there. I know several people that were sort ...

4
votes

### Before MathOverflow

The Secret Blogging Seminar used to have a Requests thread, where people could suggest topics for us to write about.

3
votes

### Requests for reopen and undelete votes for closed and deleted questions

[UNDELETED]
I propose that this question should be undeleted:
Reduced ring with all non-prime ideals finitely generated
It was deleted by the OP despite having a substantial answer by Keith Kearnes. ...

Community wiki

3
votes

### Requests for reopen and undelete votes for closed and deleted questions

[Undeleted; Reopened]
If normal with respect to prime base then normal for all bases was closed as not being research math. I nominated it for reopening, after leaving a comment establishing its ...

Community wiki

3
votes

### Requests for reopen and undelete votes for closed and deleted questions

[REOPENED]
Why did Bourbaki ignore the theory of categories? only survived 25 hours in 2013, collecting 5 answers; it has been closed ever since. The reason given (“not constructive”, “will likely ...

Community wiki

Only top scored, non community-wiki answers of a minimum length are eligible

#### Related Tags

big-list × 8discussion × 7

support × 1

feature-request × 1

bug × 1

mathjax × 1

design × 1

math-stackexchange × 1

site-promotion × 1

undelete-request × 1

re-open × 1