Semicocycle discontinuities for substitutions and reverse-reading automata

Abstract

In this article we define the semigroup associated to a substitution. We use it to construct a minimal automaton which generates a substitution sequence u in reverse reading. We show, in the case where the substitution has a coincidence, that this automaton completely describes the semicocycle discontinuities of u.

17 pages, 2 figures. This second version is re-written and improved