Ensuring Termination by Typability

A term terminates if all its reduction sequences are of finite length. Weshow four type systems that ensure termination of well-typed π-calculus processes.The systems are obtained by successive refinements of the types of the simply typedπ-calculus. For all (but one of) the type systems we also present upper bounds to thenumber of steps well-typed processes take to terminate. The termination proofs usetechniques from term rewriting systems.We show the usefulness of the type systems on some non-trivial examples: the encodingsof primitive recursive functions, the protocol for encoding separate choice in terms ofparallel composition, a symbol table implemented as a dynamic chain of cells.