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Yves Benoist

Publications and source records attributed to Yves Benoist.

25 records · Page 2Linked to original sources

Recurrence on Affine Grassmannians

We study the action of the affine group $G$ of $\mathbb{R}^d$ on the space $X_{k,\,d}$ of $k$-dimensional affine subspaces. Given a compactly-supported Zariski dense probability measure $μ$ on $G$, we show that $X_{k,\,d}$ supports a $μ$-stationary measure $ν$ if and only if the $(k\!+\!1)^{\rm th}$-Lyapunov exponent of $μ$ is strictly negative. In particular, when $μ$ is symmetric, $ν$ exists if and only if $2k\geq d$.

math.DS↗

A spectral gap theorem in simple Lie groups

We establish the spectral gap property for dense subgroups generated by algebraic elements in any compact simple Lie group, generalizing earlier results of Bourgain and Gamburd for unitary groups.

math.RT↗

Temperedness of reductive homogeneous spaces

Let G be a semisimple algebraic Lie group and H a reductive subgroup. We find geometrically the best even integer p for which the representation of G in L^2(G/H) is almost L^{p}. As an application, we give a criterion which detects whether this representation is tempered.

math.RT↗

Polar decomposition for p-adic symmetric spaces

Let G be the group of k-points of a connected reductive k-group and H a symmetric subgroup associated to an involution s of G. We prove a polar decomposition G=KAH for the symmetric space G/H over any local field k of characteristic not 2. Here K is a compact subset of G and A is a finite union of the groups of k-points of maximal (k,s)-split tori, one for each H-conjugacy class. This decomposition is analogous to the well-known polar decomposition G=KAH for a real symmetric space G/H.

math.GR↗