pages On Generative Parallel Composition

katoeninformatikunierlangende A major reason for studying probabilistic processes is to establish a link between a formal model for describing functional system behaviour and a stochastic process Compositionality is an essential ingredient for specifying systems Parallel compo sition in a probabilistic setting is complicated since it gives rise to nondeterminism for instance due to interleaving of independent autonomous activities This paper presents a detailed study of the resolution of nondeterminism in an asynchronous generative setting Based on the intuition behind the synchronous probabilistic cal culus PCCS we formulate two criteria that an asynchronous parallel composition should fulll We provide novel probabilistic variants of parallel composition for CCS and CSP and show that these operators satisfy these general criteria opposed to most existing proposals Probabilistic bisimulation is shown to be a congruence for these operators and their expansion is addressed Key words bisimulation bundle transition systems CCS CS