The Chain Relation in Sofic Subshifts

The paper gives a characterisation of the chain relation of a sofic subshift. Every sofic subshift Σ can be described by a labelled graph G. Factorising G in a suitable way we obtain the graph G/≈ that offers insight into some properties of the original subshift. Using G/≈ we describe first the chain relation in Σ, then characterise chain-transitive sofic subshifts, chain-mixing sofic subshifts and finally the attractors of the subshift dynamic system. At the end we present (straightforward) algorithms deciding chain-transitivity and chain-mixing properties of a sofic subshift and listing all the attractors of the subshift system.