Programming Research Group Technical Report TR-11-95

Argument duplication in probabilistic CSP

Carroll Morgan, Annabelle McIver, Karen Seidel, J W Sanders

October 1995, 25pp

In "Refinement oriented probability for CSP" a space PCSP of probabilistic processes is constructed uniformly from the standard CSP failures-divergences model.

Laws of CSP (whether expressing equivalence or refinement) are shown to be valid
in PCSP also, provided they have no duplication on either side: thus for example (writing |¯| for non-deterministic choice) A |¯| B = B |¯| A carries over to PCSP;
but A |¯| A = A does not, because of the duplication on its left-hand side.

Here we propose two devices for retaining more of CSP's laws within PCSP: the first introduces a limited form of state; the second allows multiple occurences of a term to be abstracted to a single syntactic location.

"Refinement oriented probability for CSP" (available as PRG Technical Report PRG-TR-12-94 or its published revision ) is prerequisite for understanding this report fully, although skimming Sec 4 and App A may give an idea of what has been achieved.


This paper is available as a 66,165 byte gzipped PostScript file.