A combinatorial problem on Trapezoidal words

In this paper, we investigate some combinatorial properties concerning the family of the so-called Trapezoidal words. Trapezoidal words, considered in de Luca (Theoret. Comput. Sci. 218 (1999) 13-39 are finite words over the two-letter alphabet A={a,b} whose subword complexity has the same behaviour as that of finite Sturmian words. In de Luca (Theoret. Comput. Sci. 218 (1999) 13-39 it has been proved that the family of Finite Sturmian words is properly contained in that one of Trapezoidal words. We carry on with the studying of the family of Trapezoidal words and, in particular, of its relation with that one of finite Sturmian words.