On commuting elements and embeddings of graph groups and monoids
Abstract
Description
We study commutation properties of subsets of right-angled Artin groups and trace monoids. We show that if Gamma is any graph not containing a four-cycle without chords, then the group G(Gamma) does not contain four elements whose commutation graph is a four-cycle; a consequence is that G(Gamma) does not have a subgroup isomorphic to a direct product of non-abelian free groups. We also obtain corresponding and more general results for monoids.
14 pages, 1 figure, typos fixed, introduction improved slightly, results unchanged
14 pages, 1 figure, typos fixed, introduction improved slightly, results unchanged