  We first present a probabilistic version of ACP that rests on the principle
that probabilistic choices are always resolved before choices involved in
alternative composition and parallel composition are resolved and then extend
this probabilistic version of ACP with a form of interleaving in which parallel
processes are interleaved according to what is known as a process-scheduling
policy in the field of operating systems. We use the term strategic
interleaving for this more constrained form of interleaving. The extension
covers probabilistic process-scheduling policies.
