In a recent paper we introduced Parikh slender languages as a generalization of slender languages defined and studied by AndraSiu, Dassow, Pgun and Salomaa. Results concerning Pa&h slender languagesâ€¦ (More)

We study the equality problem for infinite words obtained by iterating morphisms. In particular, we give a practical algorithm to decide whether or not two words generated by primitive morphisms areâ€¦ (More)

A language L is called thin if for almost all n there is at most one word of length n in L. A language L is called slender if there is a positive integer k such that for any n there are at most kâ€¦ (More)

We study the freeness problem for matrix semigroups. We show that the freeness problem is decidable for upper-triangular 2 Ã— 2 matrices with rational entries when the products are restricted toâ€¦ (More)

Recerlt work in the theory of co&c : n3 L codes (see [4]) has led to prcb%xs dealing with the representation of positive integers in arbitrary number systems. Here *arbitraryâ€™ means that the digitsâ€¦ (More)