Stationary probability measures on projective spaces

Sun Nov 12, 2023 4:00 p.m.—5:00 p.m.
Exterior of Sheffield-Sterling-Strathcona Hall featuring a stone carving of Yale's coat of arms and motto

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Seminar: 
Group Actions, Geometry and Dynamics

Event time: 
Monday, November 13, 2023 - 4:00pm

Location: 
KT801

Speaker: 
Cagri Sert

Speaker affiliation: 
University of Zurich

Event description: 
We give a description of stationary probability measures on projective spaces for
an iid random walk on GLd(R) without any algebraic assumptions. This is done
in two parts. In a first part, we study the case (non-critical or block-dominated
case) where the random walk has distinct deterministic exponents in the sense of
Furstenberg-Kifer-Hennion. In a second part (critical case), we show that if the
random walk has only one deterministic exponent, then any stationary probability
measure on the projective space lives on a subspace on which the ambient group of
the random walk acts completely reducibly. This connects the critical setting with
the work of Guivarc’h-Raugi and Benoist-Quint. Combination of all these works
allow to get a description of stationary probability measures. Joint works with Richard Aoun.