Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options questions only not deleted user 4721

Questions that are about research in mathematics, or about the job of a research mathematician, without being mathematical problems or statements in the strictest sense. Do not use this tag for easy or supposedly easy mathematical questions.

54 votes
7 answers
4k views

How to know if somebody else is also working on your problem?

Once you have spotted a mathematical problem that (presumably) fits your degree of expertise, whether you are a phd student or an established professor, you have to deal with the following non mathema …
12 votes
2 answers
1k views

Geometric meaning of small extensions ?

Let $(A,\mathfrak{m}_A)$ be a local Artinian $k$-algebra with residue field $k$. Then the scheme $\mathrm{Spec}(A)$ can be loosely seen as a "fat point", or an "infinitesimal neighbourhood" of a point …
Qfwfq's user avatar
  • 23.4k
24 votes
8 answers
39k views

A symbol to denote the set of prime numbers ?

It strikes me that there is no widely accepted symbol to denote the set of usual prime numbers in $\mathbb{N}$. Look: $$\zeta(s)=\prod_{p\in \mathrm{?}}\frac{1}{(1-p^{-s})}$$ Wouldn't it be nicer …
5 votes
2 answers
841 views

About Kodaira's book on deformations

I happened to read the following sentence in the blog by the physicist Jacques Distler: "What makes Kodaira’s Complex Manifolds and Deformation of Complex Structures such a delight to read is that …
Qfwfq's user avatar
  • 23.4k
3 votes
2 answers
441 views

Heuristics for 2-morphisms of (algebraic) stacks

For topological spaces and simplicial sets one can consider each pair of parallel morphisms $f,g:X\rightrightarrows Y$ as equipped with a set of 2-morphisms given by homotopies $H:f\simeq g$ (let's ig …
Qfwfq's user avatar
  • 23.4k
41 votes
1 answer
3k views

Are there any "homotopical spaces"?

This is a somewhat vague question; I don't know how "soft" it is, and even if it makes sense. [Edit: in the light of the comments, we can state my question in a formally precise way, that is: "Is th …
Qfwfq's user avatar
  • 23.4k
13 votes
3 answers
2k views

What's so "schematic" about schemes?

Well, the title clearly follows the title of this question. Why the objects so successfully defined by Grothendieck have been called "schemes"? In my opinion the original French word (schéma) doesn't …
Qfwfq's user avatar
  • 23.4k
10 votes
5 answers
2k views

The use of the word "model" in Mathematical Logic vs the same word in Natural Sciences [closed]

I have always been wondering why the term "model" is used by mathematicians (especially in mathematical logic) in a conceptually different (even opposite) way than it is used by other scientists, …
Qfwfq's user avatar
  • 23.4k
13 votes
1 answer
2k views

Convenient definition of "category of Riemannian manifolds"?

Has a notion of "category of Riemannian manifolds" been defined and used in the literature? For which reasons is it or would it (not) be a useful notion? I think the objects should be all (perhaps c …
Qfwfq's user avatar
  • 23.4k
48 votes
12 answers
9k views

How to explain to an engineer what algebraic geometry is?

This question is similar to this one in that I'm asking about how to introduce a mathematical research topic or activity to a non-mathematician: in this case algebraic geometry, intended as the most c …
75 votes
14 answers
6k views

Why is Set, and not Rel, so ubiquitous in mathematics?

The concept of relation in the history of mathematics, either consciously or not, has always been important: think of order relations or equivalence relations. Why was there the necessity of singling …
126 votes
15 answers
15k views

Does Physics need non-analytic smooth functions?

Observing the behaviour of a few physicists "in nature", I had the impression that among the mathematical tools they use a lot (along with possibly much more sofisticated maths, of course), there is c …
Qfwfq's user avatar
  • 23.4k
73 votes
5 answers
18k views

Mathematics of path integral: state of the art

I was told that one of the most efficient tools (e.g. in terms of computations relevant to physics, but also in terms of guessing heuristically mathematical facts) that physicists use is the so called …
23 votes
6 answers
2k views

Are rings really more fundamental objects than semi-rings?

The discovery (or invention) of negatives, which happened several centuries ago by the Chinese, Indians and Arabs, has of course be of fundamental importance to mathematics. From then on, it seems th …
12 votes
2 answers
773 views

Where does the term "torsor" come from?

Is there a heuristic reason why principal homogeneous spaces of a group (object) $G$ (in some categories) are called $G$-torsors? Does it have anything to do with the idea of "torsion", somehow? When …
Qfwfq's user avatar
  • 23.4k

15 30 50 per page