Piotr W. Nowak

collaborators

2 papers

math.GT2023

Coboundary expansion and Gromov hyperbolicity

Dawid Kielak, Piotr W. Nowak

We prove that if a compact $n$ -manifold admits a sequence of residual covers that form a coboundary expander in dimension $n - 2$ , then the manifold has Gromov-hyperbolic fundamental…

math.GR2023

On (bi)reversible automata generating lamplighter groups

Piotr W. Nowak, Andriy Oliynyk, Veronika Prokhorchuk

For any nontrivial abelian group $X$ we construct a reversible (bireversible in case the order of $X$ is odd) automaton such that its set of states and alphabet a…