Up to equivalence, a substitution in propositional logic is an endomorphism
of its free algebra. On the dual space, this results in a continuous function,
and whenever the space carries a natural measure one may ask about the
stochastic properties of the action. In classical logic there is a strong
dichotomy: while over finitely many propositional variables everything is
trivial, the study of the continuous transformations of the Cantor space is the
subject of an extensive literature, and is far from being a completed task. In
many-valued logic this dichotomy disappears: already in the finite-variable
case many interesting phenomena occur, and the present paper aims at displaying
some of these.Comment: 22 pages, 2 figures. Revised version according to the referee's
suggestions. To appear in the J. of Symbolic Logi
