A. Margolis

activity

20192022

collaborators

3 papers

math.GR2022

Counting lattices in products of trees

Nir Lazarovich, Ivan Levcovitz, Alex Margolis

A BMW group of degree $(m, n)$ is a group that acts simply transitively on vertices of the product of two regular trees of degrees $m$ and $n$ . We show that the number of commensura…

math.CO2020

Planar lattice subsets with minimal vertex boundary

Radhika Gupta, Ivan Levcovitz, Alexander Margolis +1

A subset of vertices of a graph is minimal if, within all subsets of the same size, its vertex boundary is minimal. We give a complete, geometric characterization of minimal sets f…

math.GR2019

Groups of cohomological codimension one

Alexander Margolis

We show that if $H$ is an almost normal subgroup of $G$ such that both $H$ and $G$ are of type $V F P$ and vcd( $G$ ) = vcd( $H$ ) + 1, then $G$ is the fundamental group of a graph of gr…