Linked Questions

185 votes
127 answers
65k views

Most memorable titles

Given the vast number of new papers / preprints that hit the internet everyday, one factor that may help papers stand out for a broader, though possibly more casual, audience is their title. This view ...
106 votes
83 answers
19k views

Elementary + short + useful

Imagine your-self in front of a class with very good undergraduates who plan to do mathematics (professionally) in the future. You have 30 minutes after that you do not see these students again. You ...
170 votes
47 answers
34k views

Every mathematician has only a few tricks

In Gian-Carlo Rota's "Ten lessons I wish I had been taught" he has a section, "Every mathematician has only a few tricks", where he asserts that even mathematicians like Hilbert ...
175 votes
39 answers
31k views

Short exact sequences every mathematician should know

I'd like to have a big-list of "great" short exact sequences that capture some vital phenomena. I'm learning module theory, so I'd like to get a good stock of examples to think about. An ...
66 votes
20 answers
9k views

Do mathematical objects disappear?

I am asking this question starting from two orders of considerations. Firstly, we can witness, considering the historical development of several sciences, that certain physical entities "disappeared"...
86 votes
19 answers
15k views

Each mathematician has only a few tricks

The question "Every mathematician has only a few tricks" originally had approximately the title of my question here, but originally admitted an interpretation asking for a small collection ...
47 votes
11 answers
5k views

Reference request: Examples of research on a set with interesting properties which turned out to be the empty set

I've seen internet jokes (at least more than 1) between mathematicians like this one here about someone studying a set with interesting properties. And then, after a lot of research (presumably after ...
9 votes
2 answers
674 views

Powers of finite simple groups

I have heard about the following result: for each finite simple non-abelian group $S$ and each natural number $r\ge 2$ there exists a number $n=n(r,S)$ such that the power $S^n$ is $r$-generator but $...
user 59363's user avatar
22 votes
1 answer
2k views

What is known about the common knowledge of mathematicians outside their field?

When giving a talk or writing a paper intended for non-specialist (i.e., mathematicians not specializing in the topic being discussed), the question inevitably occurs of what one can assume to be "...
2 votes
2 answers
291 views

If either $A$ is exact or $B$ is nuclear then every closed ideal of $A\otimes_{min}B$ is of the form $A \otimes _{min}J$ for some ideal $J$ of $B$

From one of the talks I attended long back, I vaguely seem to remember the following fact: Let $A$ and $B$ be $C^{\ast}$-algebras. If either $A$ is exact or $B$ is nuclear then every closed ideal of $...
Math Lover's user avatar
  • 1,115
3 votes
0 answers
895 views

Is the Kolmogorov-Arnold representation theorem an example of the Yoneda lemma?

From Wikipedia: https://en.wikipedia.org/wiki/Kolmogorov%E2%80%93Arnold_representation_theorem In real analysis and approximation theory, the Kolmogorov–Arnold representation theorem (or ...
YKY's user avatar
  • 558
0 votes
0 answers
256 views

Is the equivalence $\mathrm{CRing}^{\mathrm{op}}\simeq \mathrm{AffSch}$ related to the homotopy hypothesis?

At the heart of algebraic geometry lies the op-equivalence between commutative rings and affine schemes, i.e., $$\mathrm{CRing}^{\mathrm{op}}\simeq \mathrm{Aff\,Sch}.$$ At the heart of homotopy theory ...
Ola Sande's user avatar
  • 705