3 papers
math.GR2019
Recognizing pro-R closures of regular languages
Jorge Almeida, José Carlos Costa, Marc Zeitoun
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 sem…
cs.FL2017
The linear nature of pseudowords
Jorge Almeida, Alfredo Costa, José Carlos Costa +1
Given a pseudoword over suitable pseudovarieties, we associate to it a labeled linear order determined by the factorizations of the pseudoword. We show that, in the case of the pse…
math.GR2016
On -reducibility of pseudovarieties of the form
José Carlos Costa, Conceição Nogueira, M. Lurdes Teixeira
This paper deals with the reducibility property of semidirect products of the form relatively to graph equation systems, where denotes the pseudovariety of de…