ON THE DENSITY OF PERIODIC CONFIGURATIONS IN STRONGLY IRREDUCIBLE SUBSHIFTS
Tullio G. Ceccherini-Silberstein, Michel Coornaert · 2016
Let G be a residually finite group and let A be a finite set. We prove that if X ⊏ AG is a strongly irreducible subshift of finite type containing a periodic configuration then periodic configurations are dense in X. The density of periodic configurations implies in particular that every injective endomorphism of X is surjective and that the group of automorphisms of X is residually finite. We also introduce a class of subshifts , including all strongly irreducible subshifts and all irreducible sofic subshifts, in which periodic configurations are dense.