Sharp mapping properties of Poisson transforms and the Baum-Connes conjecture

Fuente: arXiv
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Autores principales: Gimperlein, Heiko, Goffeng, Magnus
Formato: Preprint
Publicado: 2025
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author Gimperlein, Heiko
Goffeng, Magnus
author_facet Gimperlein, Heiko
Goffeng, Magnus
contents We prove a sharp, quantitative analogue of Helgason's conjecture at the level of distributions: For a semisimple Lie group $G$ of real rank one, Poisson transforms map a Sobolev space on $P\backslash G$ boundedly with closed range to an $L^2$-space on $K\backslash G$. The result is obtained for the Poisson transform studied by Knapp-Wallach under the name Szegö map, and the appropriate Sobolev spaces are defined using van Erp-Yuncken's Heisenberg calculus. The proof generalizes to show that commutators of this Poisson transform with smooth functions on the Furstenberg compactification are compact. This proves the remaining open conjecture in Julg's seminal program to establish the Baum-Connes conjecture for closed subgroups of semisimple Lie groups of real rank one.
format Preprint
id arxiv_https___arxiv_org_abs_2512_10018
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sharp mapping properties of Poisson transforms and the Baum-Connes conjecture
Gimperlein, Heiko
Goffeng, Magnus
K-Theory and Homology
Analysis of PDEs
Operator Algebras
Representation Theory
We prove a sharp, quantitative analogue of Helgason's conjecture at the level of distributions: For a semisimple Lie group $G$ of real rank one, Poisson transforms map a Sobolev space on $P\backslash G$ boundedly with closed range to an $L^2$-space on $K\backslash G$. The result is obtained for the Poisson transform studied by Knapp-Wallach under the name Szegö map, and the appropriate Sobolev spaces are defined using van Erp-Yuncken's Heisenberg calculus. The proof generalizes to show that commutators of this Poisson transform with smooth functions on the Furstenberg compactification are compact. This proves the remaining open conjecture in Julg's seminal program to establish the Baum-Connes conjecture for closed subgroups of semisimple Lie groups of real rank one.
title Sharp mapping properties of Poisson transforms and the Baum-Connes conjecture
topic K-Theory and Homology
Analysis of PDEs
Operator Algebras
Representation Theory
url https://arxiv.org/abs/2512.10018