In this paper we consider Milner’s calculus CCS enriched by a probabilistic choice operator. The calculus is given operational semantics based on probabilistic transition systems. We define operational notions of preorder and equivalence as probabilistic extensions of the simulation preorder and the bisimulation equivalence respectively. We extend existing category-theoretic techniques for solv...

We propose a general approach for defining behavioural preorders over process terms as the maximal pre–congruences induced by basic observables. We will consider three of these, that provide information about the initial communication capabilities of processes and about the possibility that processes get engaged in divergent computations. We show that the pre–congruences induced by our basic ob...

We describe a framework for compositional veri cation of nite state processes The framework is based on two ideas a subset of the logic CTL for which satisfaction is preserved under composition and a preorder on structures which captures the relation between a component and a system containing the component Satisfaction of a formula in the logic corresponds to being below a particular structure...

We describe a framework for compositional verification of finite state processes. The framework is based on two ideas: a subset of the logic CTL for which satisfaction is preserved under composition; and a preorder on structures which captures the relation between a component and a system containing the component. Satisfaction of a formula in the logic corresponds to being below a particular st...

In the standard testing theory of DeNicola-Hennessy one process is considered to be a refinement of another if every test guaranteed by the former is also guaranteed by the latter. In the domain of web services this has been recast, with processes viewed as servers and tests as clients. In this way the standard refinement preorder between servers is determined by their ability to satisfy client...

Stuttering bisimulation is a well-known behavioural equivalence that preserves CTL-X, namely CTL without the next-time operator X. Correspondingly, the stuttering simulation preorder induces a coarser behavioural equivalence that preserves the existential fragment ECTL-{X,G}, namely ECTL without the next-time X and globally G operators. While stuttering bisimulation equivalence can be computed ...

This paper introduces a novel (bi)simulation{based faster{than preorder which relates asynchronous processes with respect to their worst{case timing behavior. The studies are conducted for a conservative extension of the process algebra CCS, called TACS, which permits the speci cation of maximal time bounds of actions. TACS complements work in plain process algebras which compares asynchronous ...

We define (bi)simulations up-to a preorder and show how we can use them to provide a coinductive, (bi)simulation-like, characterisation of semantic (equivalences) preorders for processes. In particular, we can apply our results to all the semantics in the linear time-branching time spectrum that are defined by preorders coarser than the ready simulation preorder. The relation between bisimulati...

An intensional model for the programming language PCF is described, in which the types of PCF are interpreted by games, and the terms by certain “history-free” strategies. This model is shown to capture definability in PCF. More precisely, every compact strategy in the model is definable in a certain simple extension of PCF. We then introduce an intrinsic preorder on strategies, and show that i...

In this paper we define simulations up-to a preorder and show how we can use them to provide a coinductive, simulation-like, characterization of semantic preorders for processes. The result applies to a wide class of preorders, in particular to all semantic preorders coarser than the ready simulation preorder in the linear time-branching time spectrum. An interesting but unexpected result is th...