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5 votes
1 answer
230 views

Explicit Jacquet-Langlands correspondence for real reductive groups

Let $G$ be a connected reductive group over $\mathbb R$. Let $G'$ over $\mathbb R$ be an inner form of $G$ with ${}^LG={}^LG'$. By local Langlands correspondence over $\mathbb R$, if a $L$-packet of $...
Zhiyu's user avatar
  • 6,622
11 votes
0 answers
283 views

Why are there so few irreducible admissible representations of $\text{GL}(n,\mathbb{R})$ (up to infinitesimal equivalence)?

Studying Langlands's classification of irreducible admissible representations, I have been rather stunned by the following: Theorem Up to infinitesimal equivalence, all irreducible admissible ...
Daniel Miller's user avatar
1 vote
1 answer
202 views

The identity connected component of centralizers of unipotent orbits

This is, in a way, a follow up question to Unipotent orbits and intersection with Levi and pseudo-Levi subgroups. I was reading "A generalisation of the Bala–Carter theorem for nilpotent orbits&...
Matht111101111's user avatar
1 vote
1 answer
358 views

Unipotent orbits and intersection with Levi and pseudo-Levi subgroups

Given a simple complex Lie group $G$ (I might say upfront that I am mostly interested with exceptional Lie algebras) and a nilpotent orbit $\mathcal{O}\subset G$ I would like to describe the ...
Matht111101111's user avatar
0 votes
0 answers
159 views

Holomorphic automorphic/cusp forms on real Lie groups

An automorphic form on a real Lie group $G$ for a discrete subgroup $\Gamma$ is a function $f:G\to\mathbb{C}$ with some properties (see Borel’s definition in Proceedings of Symposia in PURE ...
Jun Yang's user avatar
  • 391
6 votes
1 answer
551 views

Two definitions of automorphic forms on Lie groups

My question is the about the equivalence of two definitions of automorphic forms on a semisimple Lie group. The most common definition of automorphic forms on a semisimple Lie group $G$ with respect ...
Jun Yang's user avatar
  • 391
6 votes
1 answer
764 views

What is a map for the representation theory of reductive groups?

I have finished learning about linear algebraic groups (minus their representation theory) and the associated algebraic structures (root data, root systems, etc.), and will next attempt to summarize ...
Andrew NC's user avatar
  • 2,071
12 votes
1 answer
418 views

When does a locally symmetric space have no odd degree Betti numbers?

Let $G$ be a semisimple real lie group, $K$ be a maximal compact subgroup of $G$, $\Gamma$ be a torsion-free cocompact discrete subgroup. The Betti number the locally symmetric space $X_{\Gamma}:=\...
Zhiyu's user avatar
  • 6,622
3 votes
0 answers
188 views

Non-vanishing of left- vs. right-averages over lattices in $SL(2,\mathbb{R})$

I asked the same question on MSE one week ago, but it has not received any answers. Background. Let $G=SL(2,\mathbb{R})$, let $K=SO(2)$, and let $\Gamma$ be a lattice in $G$, e.g. $SL(2,\mathbb{Z})$...
L.C. Ruth's user avatar
  • 229
6 votes
0 answers
1k views

Definition of Admissible Representation

Let $G$ be a connected, reductive group over a number field $k$. Let $v$ be a place of $k$. If $v$ is finite, an admissible representation of $G(k_v)$ is defined to be an abstract representation of $...
D_S's user avatar
  • 6,180
2 votes
0 answers
112 views

Eigenvalues of the imaginary part of the Symplectic action on Siegel upper half plane

Let $A,B\in M_n(\mathbb{R})$ and $U=A+iB$ unitary. $R=diag(r_1,r_2,…,r_n)$ is a diagonal matrix with $r_i>0, \forall i $. I need to calculate $\det(Ae^{-R}A^T+Be^{R}B^T)$. This matrix $Ae^{-R}A^T+...
HCF's user avatar
  • 31
8 votes
1 answer
1k views

Multiplicity one theorem

I am reading Dorian Goldfeld's book Automorphic forms and L functions for the groups GL(n,R) (http://www.cambridge.org/us/academic/subjects/mathematics/number-theory/automorphic-forms-and-l-functions-...
Wiener Schmidt's user avatar
1 vote
0 answers
110 views

On continuous part of the L^2 spectrum

Suppose $G$ is a real reductive Lie group and $\Gamma$ is a lattice in $G$ (of finite co-volume). I am reading Langlands's paper " On the functional equation satisfied by the Eisenstein series". I ...
Guest's user avatar
  • 61
2 votes
0 answers
250 views

characters on unipotent group

Let $G=GL_{n}$ and $N$ the maximal unipotent subgroup, $\mathbb{A}$ the ring of adeles on a number field $F$. We fix a non trivial character $\psi:F\backslash\mathbb{A}\rightarrow \mathbb{C}^{*}$. We ...
prochet's user avatar
  • 3,472
9 votes
1 answer
638 views

Borel's Paris Lectures

I am trying to read Harish-Chandra's book on automorphic forms on Semisimple Lie groups, and he keeps referring to Borel's Paris lecture notes. Does anyone have an online version of these notes or ...
admissiblecycle's user avatar
7 votes
1 answer
561 views

How does the right regular of GL(n, R) and GL(n,Qp) decompose?

The question is contained in the title. I would guess that this question is already answered in the literature. Given the reductive group $GL(n)$ over a complete local field, how does the right ...
Marc Palm's user avatar
  • 11.2k
15 votes
3 answers
1k views

There is no lattice in PSL(2,R) which contains PSL(2,Z) properly?

How can I see that there is no lattice in $G=\mathrm{PSL}_2( \mathbb{R})$ which contains $\Gamma_1=\mathrm{PSL}_2( \mathbb{Z})$ properly, or equivalently, that $X_1 =\mathrm{PSL}_2(\mathbb{Z}) \...
Marc Palm's user avatar
  • 11.2k