Decidable Properties of Monadic Functional Schemas

Abstract

A class of (monadic) functional schemas which properly includes “Ianov” flowchart schemas is defined. It is shown that the termination, divergence, and freedom problems for functional schemas are decidable. Although it is possible to translate a large class of non-free functional schemas into equivalent free functional schemas, it is shown that in general this cannot be done. It is also shown that the equivalence problem for free functional schemas is decidable. Most of the results are obtained from well-known results in formal languages and automata theory.