The Decomposition of ESM Computations

The work presented continues the exploration of the value of ESM systems as a model of concurrent computation. In [4] and [5] a true concurrent semantics for these systems is presented, where concurrent histories are represented by process objects, called computation structures. In this paper it is shown that, if one refines the notion of a computation structure in a suitable way, then each computation structure can be decomposed according to an arbitrary partitioning of the system into subsets of rules. As a result the semantics is compositional with respect to the union of sets of rules. An application to some variants of Petri nets is sketched.