The seminal theorem of Cobham has given rise during the last 40 years to a lot of works around non-standard numeration systems and has been extended to many contexts. In this paper, as a result of fifteen years of improvements, we obtain a complete and general version for the so-called substitutive sequences. Let α and β be two multiplicatively independent Perron numbers. Then, a sequence x ∈ A...

In this paper we consider rewrite systems that describe the-calculus enriched with recursive and non-recursive local deenitions by generalizing thèexplicit substitutions' used by Abadi, Cardelli, Curien, and L evy 1] to describe sharing in-terms. This leads tòexplicit cyclic substitutions' that can describe the mutual sharing of local recursive deenitions. We demonstrate how this may be used to...