Wadge Degrees of Classes of omega-Regular k-Partitions

Abstract

We develop a theory of k-partitions of the set of infinite words recognizable by classes of finite automata. The theory enables to complete proofs of existing results about topological classifications of the (aperiodic) omega-regular k-partitions and provides tools for dealing with other similar questions. In particular, we characterize the structure of Wadge degrees of (aperiodic) omega-regular $k$-partitions, prove the decidability of many related problems, and discuss their complexity.