1 citations · 1 across the 5 of their papers we have counts for
6 papers
Directional expansion in ergodic actions of countable groups
Michael Björklund, Alexander Fish
We study directional expansion for probability-measure-preserving actions of countable groups through a representation-theoretic group property, the cyclic escape property. An infi…
Trace spectra of simplices in large sets
Michael Björklund, Alexander Fish, Shrey Sanadhya
Given an ordered tuple of vectors in , let be its edge matrix. We prove that, in every fin…
Dynamics of multiplicative groups over fields and Folner-Kloosterman sums
Michael Björklund, Alexander Fish
For two countably infinite fields whose multiplicative groups are isomorphic, we examine invariant couplings between the actions that these groups induce on the additive Pontryagin…
Ehrhart spectra of large subsets of
Michael Björklund, Rickard Cullman, Alexander Fish
This paper introduces and studies the Ehrhart spectrum of a set , defined as the set of all Ehrhart polynomials of simplices with vertices in , general…
A Szemerédi type theorem for sets of positive density in approximate lattices
Michael Björklund, Alexander Fish
An extension of Szemerédi's Theorem is proved for sets of positive density in approximate lattices in general locally compact and second countable abelian groups. As a consequence,…
Simplices in large sets and directional expansion in ergodic actions
Michael Björklund, Alexander Fish
In this paper we study ergodic -actions and investigate expansion properties along cyclic subgroups. We show that under some spectral conditions there are always dire…