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14 votes
1 answer
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Definition of discrete spectrum and continuous and basic properties

I apologize if this is too basic for MO. I have an embarrassing admission to make: I don't know the actual definition of the discrete/continuous spectrum of a reductive group $G/\mathbb{Q}$ (in the ...
Alex Youcis's user avatar
8 votes
1 answer
452 views

Characterization of automorphic discrete spectra

I recently learned about automorphic spectral decomposition from the book "Spectral decomposition and Eisenstein series" by Moeglin and Waldspurger. (Let me call it M-W) I have a question ...
user avatar
7 votes
1 answer
371 views

Gelfand pair, weakly symmetric pair, and spherical pair

I am a bit confused with the relations among Gelfand pairs, weakly symmetric pairs, and spherical pairs defined in the book "Harmonic analysis on commutative spaces" written by professor ...
Hebe's user avatar
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4 votes
1 answer
263 views

Reference request - Weyl's integration formula

Is there a reference discussing in an organized way (with a proof) the Weyl integration formula for a reductive group over a local field (Archimedean or not), expressing the Haar integral on the group ...
Sasha's user avatar
  • 5,562
3 votes
0 answers
74 views

Density of the Mellin transform inside the direct integral of induced representations

I'm trying to better understand the continuous spectrum of $G = \operatorname{GL}_2(\mathbb A_{\mathbb Q})$, which is the direct integral of induced representations $\mathbf H(s) = \operatorname{Ind}_{...
D_S's user avatar
  • 6,180
3 votes
0 answers
137 views

Span of parabolic inductions of discrete series representations

Let $G$ be the $\mathbf{Q}_p$-points in a $p$-adic reductive group, and let $R(G)$ be the Grothendieck group of the category $\mathrm{Rep}(G)$ of finite-length admissible smooth complex ...
David Hansen's user avatar
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3 votes
0 answers
190 views

Harmonic analysis on reductive groups over $\mathbb{R}$

A common way of doing harmonic analysis on (the $\mathbb{R}$-points of) reductive groups over $\mathbb{R}$ seems to be to use results from semisimple groups and "see what happens on the center&...
Chris's user avatar
  • 131
2 votes
1 answer
114 views

Adjacent parabolic subgroups and proportionality to $\alpha^{\vee}$

Let $P = MN$ be a parabolic subgroup of a $p$-adic reductive group $G$ with split component $A_M$. There is bijection from the set of parabolic subgroups of $G$ with Levi $M$ and the chambers of $\...
D_S's user avatar
  • 6,180
1 vote
1 answer
114 views

Integration over a reductive group $G$ using the constant $\gamma(P)$

Let $G$ be a connected, reductive group over a $p$-adic field. Let $A_0$ be a maximal split torus of $G$ and $P = MU$ a parabolic subgroup with Levi $M$ containing $A_0$, and opposite parabolic $\...
D_S's user avatar
  • 6,180
1 vote
0 answers
86 views

The convergence of the factor $\gamma(P)$ in the Iwasawa decomposition

Let $G$ be a connected, reductive group over a $p$-adic field $k$, $A_0$ a maximal split torus of $G$, and $P = MU$ a parabolic subgroup with $M$ containing $A_0$. Let $\overline{P} = M \overline{U}$ ...
D_S's user avatar
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