Semantic subtyping for the π-calculus

Subtyping relations for the π-calculus are usually de-fined in a syntactic way, by means of structural rules. Wepropose a semantic characterisation of channel types anduse it to derive a subtyping relation.The type system we consider includes read-only andwrite-only channel types, as well as boolean combinationsof types. A set-theoretic interpretation of types is provided,in which boolean combinations are interpreted as the corre-sponding set-theoretic operations. Subtyping is defined asinclusion of the interpretations. We prove the decidability ofthe subtyping relation and sketch the subtyping algorithm.In order to fully exploit the type system, we define a vari-ant of the π-calculus where communication is subjected topattern matching that performs dynamic typecase.