π-Calculus Semantics of Moded Flat GHC

This paper presents a new operational semantics for moded Flat Guarded Horn Clauses (FGHC). π-calculus is a simple model of concurrent computation based upon the notion of naming; π-calculus agents concurrently exchange names as data via names as channels. Naming enables an agent to be encapsulated as a value and also can provide the execution view that independent states interact with one another. The semantics of π-calculus has been investigated intensively mainly from the algebraic point of view. Given an FGHC program, we can consider that the translated π-calculus statements represent the operational meaning of the source program. Such a π-calculus semantics has the following advantages: both processes and messages (terms) are represented in a uniform way, the semantics can specify nonlogical built-in predicates together with ordinary predicates and logical variables, and the various properties of π-calculus are well-understood theoretically. This paper introduces FGHC- (a subse..