Expander graphs from Curtis Tits groups

TL;DR

This paper constructs new explicit families of expander graphs with valency five for unitary groups over finite fields using nonorientable Curtis-Tits groups, contributing to graph theory and group theory.

Contribution

It introduces a novel construction of expander graphs from nonorientable Curtis-Tits groups of type A_n, expanding the toolkit for generating expanders.

Findings

New explicit families of expander graphs with valency five

Applications to unitary groups over finite fields

Enhanced understanding of group-based graph constructions

Abstract

Using the construction of a nonorientable Curtis-Tits group of type $\tilde A_n$, we obtain new explicit families of expander graphs of valency five for unitary groups over finite fields.