6,879 reputation
21241
bio website plusepsilon.de
location Uni Hamburg
age 29
visits member for 4 years, 1 month
seen Sep 25 at 13:24

Marc Palm

Postdoc in Mathematics

http://www.plusepsilon.de


Jul
20
comment Why is the double cover of $Sl(2,\mathbb{R})$ not algebraic?
Following your suggestion, I edited the title.
Jul
20
revised Why is the double cover of $Sl(2,\mathbb{R})$ not algebraic?
added 10 characters in body; edited title; edited title
Jul
20
asked How does the right regular of GL(n, R) and GL(n,Qp) decompose?
Jul
19
revised Discrete-compact duality for nonabelian groups
added 27 characters in body
Jul
19
revised Discrete-compact duality for nonabelian groups
added 272 characters in body; edited body
Jul
19
answered Discrete-compact duality for nonabelian groups
Jul
17
comment What is the relationship amongst all the different kinds of spectra?
The spectrum of a unital commutative $C^*$ algebra $A$ is defined such that $Hom_{top}(Spec(A), \mathbb{C}) = A$, the same holds for the spectra in homotopy theory with different hom. So I always understand this as a question about representable functors. Does this make sense?
Jul
16
comment Sigma Algebra that is not a topology
@Joel: Interesting, I edited the answer.
Jul
14
accepted To what extent do we know the representations of GL(2,Zp)
Jul
14
comment generalisation of GL(3,R) polar decomposition
@Carnahan: It is sometimes called polar decomposition, since $PSL_2(\mathbb{R}) / PSO(2)$ is the upper halfplane $H$, and the above decompositions give you the elements of $H$ in polar coordinates, but you are right in general.
Jul
14
comment generalisation of GL(3,R) polar decomposition
I just wanted to comment that on both sides $SO_K(3)$ works and I presumably thought you might had a typo in the question=)
Jul
13
comment generalisation of GL(3,R) polar decomposition
@em12: Btw, are sure it holds for $GL(2)$?
Jul
13
comment generalisation of GL(3,R) polar decomposition
I mean just use $\sqrt{K} m \sqrt{K}^{-1}$ and using the result for $SO(3)$. If $K$ has negative eigenvalues, this strategy does not apply, since there is a problem with $\sqrt{K}$.
Jul
13
comment generalisation of GL(3,R) polar decomposition
@Spice, I wanted to say, if $K$ induces a scalar product on $\mathbb{R}^3$, the decomposition result is the same, since all scalar products are the same, since there exists $\sqrt{K}$. Then every matrix $m$ in $End(\mathbb{R}^3)$ can be given as $m=o d o'$ for $d$ diagonal and $o,o'\in SO_K(3)$.
Jul
13
comment generalisation of GL(3,R) polar decomposition
psoitive definite symmetric matrix and $SO_K$ on both sides, than I'd say yes.
Jul
13
comment To what extent do we know the representations of GL(2,Zp)
Yes since all irreducible complex representation of $GL(2, o)$ factor through the finite group $GL(2,o/n)$ for some ideal $n$. Then using $Ind_B^G Ind_1^B 1 = Ind_1^G 1$ gives all irreducible representations.
Jul
13
revised To what extent do we know the representations of GL(2,Zp)
added 18 characters in body
Jul
13
revised To what extent do we know the representations of GL(2,Zp)
added 8 characters in body
Jul
13
asked To what extent do we know the representations of GL(2,Zp)
Jul
12
revised Sigma Algebra that is not a topology
deleted 62 characters in body