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 not deleted user 430

This tag is used if a reference is needed in a paper or textbook on a specific result.

2 votes

References request on the algebraic geometry of projective homogeneous spaces

In addition to the references already mentioned, let me recommend Dennis Snow's excellent notes on homogeneous vector bundles. They cover everything you ask for (and much more): For a description of …
Faisal's user avatar
  • 10.3k
10 votes

Three-dimensional simple Lie algebras over the rationals

I don't know if you can find the complete list written down anywhere (and I don't know how "nice" such a list would turn out to be), but let me point out that there is a lowbrow approach to this probl …
Faisal's user avatar
  • 10.3k
5 votes

Orthogonal subgroups of dual group

Lemma 2.1.3 in Rudin's Fourier Analysis on Groups does this for locally compact abelian $G$ and closed $H \leq G$. This might not the best reference (may be a bit too general for a CS readership?), bu …
Faisal's user avatar
  • 10.3k
12 votes

A reference for smooth structures on R^n

You can handle the case of $n \leq 3$ one at a time, and so the question really is about $n \geq 5$. Two important names in this regard are Kirby and Siebenmann. The Wikipedia article on the Hauptverm …
Faisal's user avatar
  • 10.3k
2 votes

Expository treatment of Schubert Cells Paper

You might enjoy this article by Harry Tamvakis.
Faisal's user avatar
  • 10.3k
5 votes
Accepted

Which formulae of Euler is Fröhlich referring to?

I believe the reference is to this formula of Euler (see here): If $P(x)/Q(x)$ is a rational function and $ax+b$ is a simple factor of $Q(x)$, then the coefficient of $1/(ax+b)$ in the partial fractio …
Faisal's user avatar
  • 10.3k
20 votes
Accepted

Unitary representations of the ax+b group: an accessible presentation

I know of two clean approaches to classifying the unitary irreps of the $ax+b$ group. The first is to write the group as a semidirect product $\mathbb R \ltimes \mathbb R_{>0}$. There is a theory (due …
Faisal's user avatar
  • 10.3k
8 votes
Accepted

Moduli Spaces of Higher Dimensional Complex Tori

The fact that all $1$-dimensional tori are projective means care is sometimes needed in making analogies with higher dimensional tori. This is one of those times. The natural 'moduli space' of all $d$ …
Faisal's user avatar
  • 10.3k
30 votes
9 answers
10k views

Diophantine equation with no integer solutions, but with solutions modulo every integer

It's probably common knowledge that there are Diophantine equations which do not admit any solutions in the integers, but which admit solutions modulo $n$ for every $n$. This fact is stated, for examp …
Faisal's user avatar
  • 10.3k
49 votes

"The complex version of Nash's theorem is not true"

Using the maximum modulus principle you can show that $\mathbb{C}^n$ doesn't have any compact complex submanifolds of positive dimension. It follows that lots of complex manifolds, such as complex gra …
Faisal's user avatar
  • 10.3k
3 votes
Accepted

Topological properties of $K$ orbits in $G/B$

If $\theta$ is an involution of a complex linear algebraic group $G$ and if $K=G^\theta$ is its fixed-point set, then $K/K^0$ will always have exponent 2. This follows from a generalized "Cartan deco …
Faisal's user avatar
  • 10.3k
3 votes
Accepted

Geometric structure of flag manifolds, Borel -Weil-Bott theorem

Correct. You can be fairly explicit here. For each root $\alpha$, let $\omega_\alpha \in \mathfrak g^\ast$ be a left-invariant form on $G$ that is dual to $\mathfrak g_\alpha$. Then for $\lambda \in …
Faisal's user avatar
  • 10.3k
5 votes

Parallel forms and cohomology of symmetric spaces

I think there's some confusion in the question. For example by "Levi-Civita connection" you must really mean some kind of Laplacian. Anyway, your end result about the cohomology of $G/H$ is essentiall …
Faisal's user avatar
  • 10.3k
4 votes
Accepted

Set of invertible operators in B(H) is connected. Is it true? Is there a reference?

You can use some spectral theory to show that the set of unitary operators in $B(H)$ is path-connected. Then the (path-)connectedness of the invertibles follows easily from the polar decomposition. Se …
Faisal's user avatar
  • 10.3k