Search Results
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 |
This tag is used if a reference is needed in a paper or textbook on a specific result.
21
votes
4
answers
4k
views
Complete (possibly official) list of "What is..." articles from the Notices of the AMS
Does it exist online and where can one find it? (For example, these two sources are not official; is the longer one complete?)
1
vote
On Ring Schemes
This is not a complete reference of course, but there is Lecture 26 (Ring Schemes; The Witt Scheme) in Mumford's book Lectures on curves on an algebraic surface
3
votes
Measures of entangledness of an open curve
Perhaps, one could define the "entangledness" of an open curve (of unit lenghth and parametrized in arclength) as the minimum
$$\mathrm{min}_{H}\;E(H), $$
over all possible smooth simple "strighten …
1
vote
1
answer
184
views
What's the name of "twisted semidirect products"?
Let $V$ be an $n$-dimensional real vector space, $\Lambda\subseteq V$ a lattice, and $K$ a subgroup of $Aut_{\mathbb{Z}}(\Lambda)\cong GL(n,\mathbb{Z})$. Let also $\sigma \in Z^1(K,V/\Lambda)$, $\sigm …
12
votes
Maxwell's equations and differential forms
M. Nakahara, Geometry, topology and physics. Paragraph 10.5 "Gauge theories", specifically 10.5.1 "$U(1)$ gauge theories".
R.S. Palais, The geometrization of physics, lecture notes from a course at N …
47
votes
11
answers
15k
views
Standard model of particle physics for mathematicians
If a mathematician who doesn't know much about the physicist's jargon and conventions had the curiosity to learn how the so called Standard Model (of particle physics, including SUSY) works, where sho …
11
votes
1
answer
2k
views
Do complete non-projective varieties arise "in nature"?
I'm aware of the existence of complete (abstract) algebraic varieties that are not projective but, probably due to my ignorance, I have the impression that they arise only as very particular examples …
19
votes
1
answer
1k
views
A result on Lie group actions on 15-dimensional spheres?
In this interview by Eric Weinstein to Roger Penrose, Timestamp 1:24:05., what result is the host talking about?
Transcription of the relevant part:
"If you have two sets of symmetries, known as Lie …
3
votes
1
answer
316
views
Equivariant characteristic classes on $\mathbb{P}^n$
Let $T=(\mathbb{C}^*)^n$ act on $\mathbb{P}^n$ torically by
$$t.[x_0:\dots:x_n]=[x_0\;:\;t_1x_1\;:\;\ldots \;:\;t_nx_n]$$
I would like to know an expression for
the equivariant Chern character $\ma …
4
votes
2
answers
382
views
About the cone being unique up to non-unique isomorphism
In an answer to this MO question [link] Fernando Muro sais:
the mapping cone of a morphism in a triangulated category is unique up
to non-unique isomorphism. This fact has originated a lot of re …
1
vote
The symmetry group of $\mathbb Z^d$
As far as I read (See page 138 of R.W.Sharpe), the Erlangen program, strictly speaking, describes connected homogeneus manifolds $X$ as $G/H$ where $G$ is a Lie group considered as the "automorphism g …
3
votes
3
answers
472
views
Undecidability and holomorphic functions (Reference request)
The goal of this question is to recall a certain mathematical fact -not in my field- that I was once briefly told and that I have fogotten, and also to collect similar results.
The fact, I think, wa …
6
votes
4
answers
2k
views
Isomorphic but non-conjugate subgroups of $GL(n,\mathbb{Z})$ ?
I've been asked some questions by a friend interested in crystallography, and the following questions (I'm not an expert) came spontaneous to me:
1) Are there two finite subgroups $P,P'\subset\mat …
21
votes
2
answers
858
views
Do Betti numbers beyond the first have a "number of cuts" interpretation?
I have heard stated the following
Theorem. If $\Sigma$ is a (orientable) surface, then $\mathrm b_1(\Sigma)$ counts the maximum number of "circular cuts" (embedded circles $C_1,\ldots,C_m$) that you …
9
votes
3
answers
2k
views
Definition of étale (etc) for non-representable morphisms of algebraic stacks?
I've stumbled upon the statement that the morphism $\pi$ from a root stack of the form $\sqrt[r]{\mathscr{L}/\mathscr{Y}}$ (i.e. the "generic" version, not the one concentrated along a divisor) to its …