Expanding measures: Random walks and rigidity on homogeneous spaces

Let G be a real Lie group, $\Lambda <G$ a lattice and $H\leqslant G$ a connected semisimple subgroup without compact factors and with finite center. We define the notion of H-expanding measures $\mu $ on H and, applying recent work of Eskin–Lindenstrauss, prove that $\mu...

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Main Authors: Roland Prohaska, Cagri Sert, Ronggang Shi
Format: Article
Language:English
Published: Cambridge University Press 2023-01-01
Series:Forum of Mathematics, Sigma
Subjects:
Online Access:https://www.cambridge.org/core/product/identifier/S2050509423000567/type/journal_article
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author Roland Prohaska
Cagri Sert
Ronggang Shi
author_facet Roland Prohaska
Cagri Sert
Ronggang Shi
author_sort Roland Prohaska
collection DOAJ
description Let G be a real Lie group, $\Lambda <G$ a lattice and $H\leqslant G$ a connected semisimple subgroup without compact factors and with finite center. We define the notion of H-expanding measures $\mu $ on H and, applying recent work of Eskin–Lindenstrauss, prove that $\mu $ -stationary probability measures on $G/\Lambda $ are homogeneous. Transferring a construction by Benoist–Quint and drawing on ideas of Eskin–Mirzakhani–Mohammadi, we construct Lyapunov/Margulis functions to show that H-expanding random walks on $G/\Lambda $ satisfy a recurrence condition and that homogeneous subspaces are repelling. Combined with a countability result, this allows us to prove equidistribution of trajectories in $G/\Lambda $ for H-expanding random walks and to obtain orbit closure descriptions. Finally, elaborating on an idea of Simmons–Weiss, we deduce Birkhoff genericity of a class of measures with respect to some diagonal flows and extend their applications to Diophantine approximation on similarity fractals to a nonconformal and weighted setting.
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spelling doaj.art-cb87515223544623894d8c071888cb292023-07-04T09:18:31ZengCambridge University PressForum of Mathematics, Sigma2050-50942023-01-011110.1017/fms.2023.56Expanding measures: Random walks and rigidity on homogeneous spacesRoland Prohaska0Cagri Sert1Ronggang Shi2Departement Mathematik, ETH Zürich, Rämistrasse 101, 8092 Zürich, Switzerland; E-mail:Institut für Mathematik, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; E-mail:Shanghai Center for Mathematical Sciences, Jiangwan Campus, Fudan University, No.2005 Songhu Road, Shanghai, 200438, China; E-mail:Let G be a real Lie group, $\Lambda <G$ a lattice and $H\leqslant G$ a connected semisimple subgroup without compact factors and with finite center. We define the notion of H-expanding measures $\mu $ on H and, applying recent work of Eskin–Lindenstrauss, prove that $\mu $ -stationary probability measures on $G/\Lambda $ are homogeneous. Transferring a construction by Benoist–Quint and drawing on ideas of Eskin–Mirzakhani–Mohammadi, we construct Lyapunov/Margulis functions to show that H-expanding random walks on $G/\Lambda $ satisfy a recurrence condition and that homogeneous subspaces are repelling. Combined with a countability result, this allows us to prove equidistribution of trajectories in $G/\Lambda $ for H-expanding random walks and to obtain orbit closure descriptions. Finally, elaborating on an idea of Simmons–Weiss, we deduce Birkhoff genericity of a class of measures with respect to some diagonal flows and extend their applications to Diophantine approximation on similarity fractals to a nonconformal and weighted setting.https://www.cambridge.org/core/product/identifier/S2050509423000567/type/journal_article60B1522F3060G5037A4428A80
spellingShingle Roland Prohaska
Cagri Sert
Ronggang Shi
Expanding measures: Random walks and rigidity on homogeneous spaces
Forum of Mathematics, Sigma
60B15
22F30
60G50
37A44
28A80
title Expanding measures: Random walks and rigidity on homogeneous spaces
title_full Expanding measures: Random walks and rigidity on homogeneous spaces
title_fullStr Expanding measures: Random walks and rigidity on homogeneous spaces
title_full_unstemmed Expanding measures: Random walks and rigidity on homogeneous spaces
title_short Expanding measures: Random walks and rigidity on homogeneous spaces
title_sort expanding measures random walks and rigidity on homogeneous spaces
topic 60B15
22F30
60G50
37A44
28A80
url https://www.cambridge.org/core/product/identifier/S2050509423000567/type/journal_article
work_keys_str_mv AT rolandprohaska expandingmeasuresrandomwalksandrigidityonhomogeneousspaces
AT cagrisert expandingmeasuresrandomwalksandrigidityonhomogeneousspaces
AT ronggangshi expandingmeasuresrandomwalksandrigidityonhomogeneousspaces