Navigating directed Cayley graphs of small diameter: A potent Solovay–Kitaev procedure

Autor: Henry Bradford
Přispěvatelé: Bradford, Henry [0000-0003-2949-8095], Apollo - University of Cambridge Repository
Rok vydání: 2020
Předmět:
DOI: 10.17863/cam.50292
Popis: Let [Formula: see text] be a group and [Formula: see text] be a descending sequence of finite-index normal subgroups. We establish explicit upper bounds on the diameters of the directed Cayley graphs of the [Formula: see text], under some natural hypotheses on the behavior of power and commutator words in [Formula: see text]. The bounds we obtain do not depend on a choice of generating set. Moreover, under reasonable conditions our method provides a fast algorithm for navigating directed Cayley graphs. The proof is closely analogous to the Solovay–Kitaev procedure, which only uses commutator words, but also only constructs small-diameter undirected Cayley graphs. We apply our procedure to give new directed diameter bounds on finite quotients of a large class of regular branch groups, and of [Formula: see text] (for [Formula: see text] even).
Databáze: OpenAIRE