4 citations · 5 across the 5 of their papers we have counts for
5 papers
Greenberg-Shalom's Commensurator Hypothesis and Applications
Nic Brody, David Fisher, Mahan Mj +1
We discuss many surprising implications of a positive answer to a question raised in some cases by Greenberg in the s and more generally by Shalom in the early s. We ref…
Co-spectral radius of intersections
Mikolaj Fraczyk, Wouter van Limbeek
We study the behavior of the co-spectral radius of a subgroup of a discrete group under taking intersections. Our main result is that the co-spectral radius of an invariant…
Commensurators of normal subgroups of lattices
David Fisher, Mahan Mj, Wouter Van Limbeek
We study a question of Greenberg-Shalom concerning arithmeticity of discrete subgroups of semisimple Lie groups with dense commensurators. We answer this question positively for no…
Heat kernels are not uniform expanders
Mikolaj Fraczyk, Wouter van Limbeek
We study infinite analogues of expander graphs, namely graphs where subgraphs weighted by heat kernels form an expander family. Our main result is that there does not exist any inf…
Isometry types of frame bundles
Wouter van Limbeek
We consider the orthonormal frame bundle F(M) of a Riemannian manifold M. A construction of Sasaki defines a canonical Riemannian metric on F(M). We prove that for two closed Riema…