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arXiv · 1905.10460

Recognizing pro-R closures of regular languages

Jorge Almeida·José Carlos Costa·Marc Zeitoun
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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.

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Jorge Almeida, José Carlos Costa, Marc Zeitoun. 2019-05-24. Recognizing pro-R closures of regular languages. https://doi.org/10.1515/forum-2019-0158

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