Strong topological Rokhlin property, shadowing, and symbolic dynamics of countable groups

A countable group G has the strong topological Rokhlin property (STRP) if it admits a continuous action on the Cantor space with a comeager conjugacy class. We show that having STRP is a symbolic dynamical property. We prove that a countable group G has STRP if and only if certain sofic subshifts over G are dense in the space of subshifts. A sufficient condition is that isolated shifts over G are dense in the space of all subshifts.We provide numerous applications including the proof that a group that decomposes as a free product of finite or cyclic groups has STRP. We show that finitely generated nilpotent groups do not have STRP unless they are virtually cyclic; the same is true for many groups of the form G_{1}\times G_{2}\allowbreak\times\nobreak G_{3} where each factor is recursively presented. We show that a large class of non-finitely-generated groups do not have STRP; this includes any group with infinitely generated center and the Hall universal locally finite group.We find a very strong connection between STRP and shadowing, also called the pseudo-orbit tracing property. We show that shadowing is generic for actions of a finitely generated group G if and only if G has STRP.