Refining multiset transformers

AbstractGamma is a minimal language based on local multiset rewriting with an elegant chemical reaction metaphor. The virtues of this paradigm in terms of systematic program construction and design of parallel programs have been argued in previous papers. Gamma can also be seen as a notation for coordinating independent programs in a larger application. In this paper, we study a notion of refinement for programs involving parallel and sequential composition operators, and derive a number of programming laws. The calculus thus obtained is applied in the development of a generic “pipelining” transformation, which enables certain sequential compositions to be refined into parallel compositions