EPISTURMIAN WORDS: SHIFTS, MORPHISMS AND NUMERATION SYSTEMS
Jacques Justin, Giuseppe Pirillo · International Journal of Foundations of Computer Science · 2004
Episturmian words, which include the Arnoux-Rauzy sequences, are infinite words on a finite alphabet generalizing the Sturmian words and sharing many of their same properties. This was studied in previous papers. Here we gain a deeper insight into these properties. This leads in particular to consider numerations systems similar to the Ostrowski ones and to give a matrix formula for computing the number of representations of an integer in such a system. We also obtain a complete answer to the question: if an episturmian word is morphic, which shifts of it, if any, also are morphic ?