The Synchronic Group: A Concurrent Programming Concept and Its Proof Logic

Swarm is a computational model which extends UNITY in three important ways: (1) UNITY's fixed set of variables is replaced by an unbounded set of tuples which are addressed by content rather than by name; (2) UNITY's static set of statements is replaced by a dynamic set of transactions; and (3) UNITY's static IIcomposition is augmented by dynamic coupling of transactions into synchronic groups. This paper overviews the Swarm model, introduced the synchronic group concept, and illustrates their use in the expression of dynamically structured programs. A UNITY-style programming logic is given for SWARM, the first axiomatic proof system for a shared database language.