Abstract
In this paper, we give some resuts on primitive words, square-free words and disjunctive languages. We show that for a word u∈∑+, every element of λ(cp(u)) is d-primitive if it is square-free, where cp(u) is the set of all cyclic-permutations of u, and λ(cp(u)) is the set of all primitive roots of it. Next we show that pmqn is a primitive word for every n, m≥1 and primitive words p, q, under the condition that |p|=|q| and (m, n)≠(1, 1). We also give a condition of disjunctiveness for a language.
