Eecient Parallel Execution and Transformation of Forward Branching Term Rewriting Systems

Sekar and al. found an eecient parallel reduction strategy for the class of path sequential term rewriting systems, which follow the constructor discipline. In this article, we present an overview of a parallel reduction strategy for the extended class of nonconstructor path sequential systems. We then deene formally this class and show some of its properties. Moreover, we give a transformation which transforms every forward branching system with a nonconstructor path sequential one. The size of the system increases only modestly over that of the original one in many practical situation. We give an algorithm for this transformation and we prove its correctness and completeness. The new system is then proved to be equivalent to the input system, with respect to the behavior and the semantics.