Translation-like Actions and Aperiodic Subshifts on Groups
Abstract
It is well known that if G admits a f.g. subgroup H with a weaklyaperiodic SFT (resp. an undecidable domino problem), then Gitself has a weakly aperiodic SFT (resp. an undecidable domino problem).We prove that we can replace the property "H is a subgroup of G"by "H acts translation-like on G", provided H is finitely presented.In particular:* If G\1 and G\2 are f.g. infinite groups, then G\1 × G\2 has a weakly aperiodic SFT (and actually a undecidable domino problem). In particular the Grigorchuk group has an undecidable domino problem. * Every infinite f.g. p-group admits a weakly aperiodic SFT.
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