A Semantic Approach to Protocold using Process Algebra

Abstract

We study of the operational behaviour of the specification language Protocold. We examine whether BPA(+) (Basic Process Algebra with backtracking) forms a useful basis for a clear representation of the execution of certain language constructs from Protocold. Our primary focus is on those constructs that contain some form of backtracking. Backtracking in Protocold contains the undoing of bindings of object names (logical variables). We first provide a short introduction to both formalisms, and then make a rough comparison of them both. Some elementary Protocold features, such as object names and the binding of object names, are then defined relative to a special data environment for BPA(+). Finally, a small language PCL is defined for the description of the operational behaviour of Protocold-like expressions, as well as a mapping from \Sigma(PC L) expressions to \Sigma(BPA(+)) terms. Some operational equivalences that hold in Protocold are defined as rules in PCL , such that algebraic m..