A model of higher-order concurrent programs based on graph rewriting

This article presents a formal model of concurrent systems with higher-order communication to transfer program codes as data between processes. A number of models [1,14,15] are reported as models of higher-order communication and most of them are based on process algebra. However as we reported [7, 8], it is not easy to represent the scopes of names of communication channels precisely using process algebra. We present a model of concurrent programs with higher order communication that can represent the scopes of names precisely. The model presented here is an extension of the model reported in [8] that is based on graph rewriting. We define the equivalence relation such that if the equivalence holds on two programs then they are equivalent not only on their behaviors but on the scopes of names also. This article also presents a compilation of higher-order concurrent programs into first-order name passing programs on the graph rewriting model.