Let G/H be a unimodular real spherical space which is either absolutely spherical or wave-front. It is shown that every tempered representation of G/H embeds into a relative discrete series of a boundary degeneration of G/H. If in addition G/H is of wave-front type it follows that the tempered representation is parabolically induced from a discrete series representation of a lower dimensional real spherical space. Final version. To appear in Acta Math.
Let $Z$ be a unimodular real spherical space. We develop a theory of constant terms for tempered functions on $Z$ which parallels the work of Harish-Chandra. The constant terms $f_I$ of an eigenfunction $f$ are parametrized by subsets $I$ of the set $S$ of spherical roots which determine the fine geometry of $Z$ at infinity. Constant terms are transitive i.e. $(f_J)_I=f_I$ for $I\subset J$, and our main result is a quantitative bound of the difference $f-f_I$, which is uniform in the parameter of the eigenfunction.
Let S(X) be the Schwartz space of compactly supported smooth functions on the p-adic points of a spherical variety X, and let C(X) be the space of Harish-Chandra Schwartz functions. Under assumptions on the spherical variety, which are satisfied when it is symmetric, we prove Paley-Wiener theorems for the two spaces, characterizing them in terms of their spectral transforms. As a corollary, we get relative analogs of the smooth and tempered Bernstein centers -- rings of multipliers for S(X) and C(X). When X= a reductive group, our theorem for C(X) specializes to the well-known theorem of Haris…
For an unramified connected reductive group $G$ defined over a number field $F$, consider the part of the spherical automorphic spectrum with cuspidal support $[T,\mathcal{O}(χ)]$, where $T$ is a maximal torus and $χ$ is an unramified automorphic character. We define a normalization of the Eisenstein series and we give the precise spectral decomposition of the closure of the subspace spanned by the normalized pseudo-Eiseinstein series. The proof uses residue distributions which were introduced by the third author (in joint work with G. Heckman) in the study of graded affine Hecke algebras, whi…
A twisted Hecke algebra, then and now, and a Klein bottle of tempered representations
Sorbonne Université（索邦大学）；Université Paris Cité（巴黎西岱大学）；CNRS, IMJ-PRG（法国国家科学研究中心，IMJ-PRG）；School of Mathematics, Southampton University（南安普顿大学数学学院）；School of Mathematics, Manchester University（曼彻斯特大学数学学院）
We study the auto-correlation measures of invariant random point processes in the hyperbolic plane which arise from various classes of aperiodic Delone sets. More generally, we study auto-correlation measures for large classes of Delone sets in (and even translation bounded measures on) arbitrary locally compact homogeneous metric spaces. We then specialize to the case of weighted model sets, in which we are able to derive more concrete formulas for the auto-correlation. In the case of Riemannian symmetric spaces we also explain how the auto-correlation of a weighted model set in a Riemannian …
We consider compact locally symmetric spaces $Γ\backslash G/H$ where $G/H$ is a non-compact semisimple symmetric space and $Γ$ is a discrete subgroup of $G$. We discuss some features of the joint spectrum of the (commutative) algebra $D(G/H)$ of invariant differential operators acting, as unbounded operators, on the Hilbert space $L^2(Γ\backslash G/H)$ of square integrable complex functions on $Γ\backslash G/H$. In the case of the Lorentzian symmetric space $SO_0(2,2n)/SO_0(1,2n)$, the representation theoretic spectrum is described explicitly. The strategy is to consider connected reductive Li…
Let $G$ be a split reductive group over a number field $F$. We consider the computation of the inner product of two $K$-spherical pseudo Eisenstein series of $G$ supported in $[T,\mathcal{O}(1)]$ by means of residues, following a classical approach initiated by Langlands. We show that only the singularities of the intertwining operators due to the poles of the completed Dedekind zeta function $Λ_F$ contribute to the spectrum, while the singularities caused by the zeroes of $Λ_F$ do not contribute to any of the iterated residues which arise as a result of the necessary contour shifts. In the co…
The spectrum of $L^2$ on a pseudo-unitary group $U(p,q)$ (we assume $p\ge q$ naturally splits into $q+1$ types. We write explicitly orthogonal projectors in $L^2$ to subspaces with uniform spectra (this is an old question formulated by Gelfand and Gindikin). We also write two finer separations of $L^2$. In the first case pieces are enumerated by $r=0$, 1,..., $q$ and representations of discrete series of $U(p-r,q-r)$, where $r=0$, \dots, $q$. In the second case pieces are enumerated by all discrete parameters of the tempered spectrum of $U(p,q)$.
On the unramified spectrum of spherical varieties over p-adic fields
群G的不可约表示的描述可以看作是调和分析中的一个问题;也就是说，通过左乘和右乘将G上的一个合适的函数空间分解成G x G的作用的不可约表示。对于局部非阿基米德域上的可裂p-adic约化群G，非分歧不可约光滑表示与"Langlands对偶“群中的半单共轭类成双射。我们将这种描述推广到G的任意球面簇X上，如下：空间$C_c^\infty(X)$的不可约非分歧子是自然的"几乎双射“，其中有许多$A_X^*/W_X$的副本，一个复环面与X的"小外尔群”的商。这导致了对非分歧向量的Hecke模的描述（Gaitsgory和Nadler的几何结果的弱模拟），并理解了某些子群的表示是函子提升的现象。在证明过程中，考察了球面簇的合理性性质，并对F. Knop，在Borel轨道集合上的外尔群。
