English

Recognizing pro-R closures of regular languages

Group Theory 2023-01-31 v1 Formal Languages and Automata Theory

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.

Keywords

Cite

@article{arxiv.1905.10460,
  title  = {Recognizing pro-R closures of regular languages},
  author = {Jorge Almeida and José Carlos Costa and Marc Zeitoun},
  journal= {arXiv preprint arXiv:1905.10460},
  year   = {2023}
}
R2 v1 2026-06-23T09:23:18.756Z