Eigenfunction expansions of functions describing systems with symmetries.
Eigenspaces of Invariant Differential Operators on an Affine Symmetric Space.
Eigenvalues of sums of hermitian matrices
Ellipticity of the symplectic twistor complex
For a Fedosov manifold (symplectic manifold equipped with a symplectic torsion-free affine connection) admitting a metaplectic structure, we shall investigate two sequences of first order differential operators acting on sections of certain infinite rank vector bundles defined over this manifold. The differential operators are symplectic analogues of the twistor operators known from Riemannian or Lorentzian spin geometry. It is known that the mentioned sequences form complexes if the symplectic...
Endoscopic groups and packets of non-tempered representations
Equivariant deformation quantization for the cotangent bundle of a flag manifold
Let be a (generalized) flag manifold of a complex semisimple Lie group . We investigate the problem of constructing a graded star product on which corresponds to a -equivariant quantization of symbols into twisted differential operators acting on half-forms on . We construct, when is generated by the momentum functions for , a preferred choice of where has the form . Here are operators on . In the known examples, () is not a differential operator, and so the star product ...
Ergodic decomposition for pairs of lattices in Lie groups.
Erratum: A Geometric Construction of the Discrete Series for Semisimple Lie Groups.
Erratum : “-Whittaker vectors for complex semisimple Lie groups, wave front sets, and Goldie rank polynomial representations”
Erratum : “Closed orbits and tempered orbits”
Existence of compact quotients of homogeneous spaces, measurably proper actions, and decay of matrix coefficients
Explicit Hilbert spaces for certain unipotent representations.
Explicit Kazhdan constants for representations of semisimple and arithmetic groups
Consider a simple non-compact algebraic group, over any locally compact non-discrete field, which has Kazhdan’s property . For any such group, , we present a Kazhdan set of two elements, and compute its best Kazhdan constant. Then, settling a question raised by Serre and by de la Harpe and Valette, explicit Kazhdan constants for every lattice in are obtained, for a “geometric” generating set of the form , where is a ball of radius , and the dependence of on is described explicitly....
Exponents in Archimedean Arthur packets
Generalizing the proof – by Hecht and Schmid – of Osborne’s conjecture we prove an Archimedean (and weaker) version of a theorem of Colette Moeglin. The result we obtain is a precise Archimedean version of the general principle – stated by the second author – according to which a local Arthur packet contains the corresponding local -packet and representations which are more tempered.
Extension of Wang-Gong monotonicity result in semisimple Lie groups
We extend a monotonicity result of Wang and Gong on the product of positive definite matrices in the context of semisimple Lie groups. A similar result on singular values is also obtained.
Extensions of Three Matrix Inequalities to Semisimple Lie Groups
We give extensions of inequalities of Araki-Lieb-Thirring, Audenaert, and Simon, in the context of semisimple Lie groups.