Wyniki wyszukiwania - BazTech

Ograniczanie wyników

3 Fundamenta Informaticae

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Epichristoffel Words and Minimization of Moore Automata

Castiglione G., Sciortino M.

Fundamenta Informaticae

2014

Vol. 134, nr 3/4

319--333

This paper is focused on the connection between the combinatorics of words and minimization of automata. The three main ingredients are the epichristoffel words, Moore automata and a variant of Hopcroft’s algorithm for their minimization. Epichristoffel words defined in [14] generalize some properties of circular sturmian words. Here we prove a factorization property and the existence of the reduction tree, that uniquely identifies the structure of the word. Furthermore, in the paper we investigate the problem of the minimization of Moore automata by defining a variant of Hopcroft’s minimization algorithm. The use of this variant makes simpler the computation of the running time and consequently the study of families of automata that represent the extremal cases of the minimization process. Indeed, such a variant allows to use the above mentioned factorization property of the epichristoffel words and their reduction trees in order to find an infinite family of Moore automata such that the execution of the algorithm is uniquely determined and tight.

On the Shuffle of Star-Free Languages

Castiglione G., Restivo A.

Fundamenta Informaticae

2012

Vol. 116, nr 1-4

35-44

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 starfree. Some of the special cases here approached give rise to new problems in combinatorics on words.

Higman's Theorem on Discrete Sets

Burderi F., Castiglione G., Restivo A.

Fundamenta Informaticae

2006

Vol. 74, nr 4

435-446

In this paper we investigate properties of different classes of discrete sets with respect to the partial-order of subpicture. In particular we take in consideration the classes of convex polyominoes and L-convex polyominoes. In the first part of the paper we study closure properties of these classes with respect the order and we give a new characterization of L-convex polyominoes. In the second part we pose the question to extend Higman's theorem to discrete sets. We give a negative answer in the general case and we prove that the set of L-convex polyominoes is well-partially-ordered by using a representation of L-convex polyominoes in terms of words of a regular language.