Affiliations: Dipartimento di Matematica e Informatica, Universitá di Palermo, Via Archirafi 34, 90123 Palermo, Italy, giusi@math.unipa.it | Dipartimento di Matematica e Informatica, Universitá di Palermo, Via Archirafi 34, 90123 Palermo, Italy, restivo@math.unipa.it
Note: [] Address for correspondence: Dipartimento di Matematica e Informatica, Universitá di Palermo, Via Archirafi 34, 90123 Palermo, Italy
Abstract: Motivated by the general problem to characterize families of languages closed under shuffle, we investigate some conditions under which the shuffle of two star-free languages is star-free. Some of the special cases here approached give rise to new problems in combinatorics on words.
Keywords: Regular languages, star-free languages, shuffle of languages, pure submonoids, combinatorics on words
