2000 character limit reached
Recognizing pro-R closures of regular languages (1905.10460v1)
Published 24 May 2019 in math.GR and cs.FL
Abstract: Given a regular language L, we effectively construct a unary semigroup that recognizes the topological closure of L in the free unary semigroup relative to the variety of unary semigroups generated by the pseudovariety R of all finite R-trivial semigroups. In particular, we obtain a new effective solution of the separation problem of regular languages by R-languages.