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22
Proving Properties of Dynamic Process Networks
, 1998
"... We present the first compositional proof system for checking processes against formulas in the modal ¯calculus which is capable of handling dynamic process networks. The proof system is obtained in a systematic way from the operational semantics of the underlying process algebra. A nontrivial proo ..."
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Cited by 18 (9 self)
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We present the first compositional proof system for checking processes against formulas in the modal ¯calculus which is capable of handling dynamic process networks. The proof system is obtained in a systematic way from the operational semantics of the underlying process algebra. A nontrivial proof example is given, and the proof system is shown to be sound in general, and complete for finitestate processes. 1 Introduction In this paper we address the problem of verifying modal ¯calculus properties of general infinitestate processes, and we present what we believe to be the first genuinely compositional solution to this problem. The value of compositionality in program logics is well established. Compositionality allows better structuring and decomposition of the verification task, it allows reuse of proofs, and it allows reasoning about partially instantiated programs, thus supporting program synthesis. Even more fundamentally it allows, at least in principle, verification exe...
Proving Trust in Systems of SecondOrder Processes: Preliminary results
 In Proceedings of the 31th Hawaii International Conference on System Sciences, volume VII
, 1997
"... We consider the problem of proving correctness properties for concurrent systems with features such as higherorder communication and dynamic resource generation. As examples we consider operational models of security and authentication protocols based on the higherorder calculus. In the setting ..."
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Cited by 15 (1 self)
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We consider the problem of proving correctness properties for concurrent systems with features such as higherorder communication and dynamic resource generation. As examples we consider operational models of security and authentication protocols based on the higherorder calculus. In the setting we propose key features such as nonces/time stamps, encryption /decryption, and key generation can be modelled in a simple and abstract fashion using channel name generation and secondorder process communication. A temporal logic is proposed as an appropriate logic to express crucial correctness properties such as secrecy and authenticity. The logic is based on the modal calculus with only greatest fixed points and universal nextstate quantification, extended with firstorder features to deal with names, and secondorder features including function space constructions to deal with process input and output. A difficulty is that formulas need recursion in both covariant and contravariant po...
Compositional Verification of CCS Processes
, 1999
"... . We present a proof system for verifying CCS processes in the modal ¯calculus. Its novelty lies in the generality of the proof judgements allowing parametric and compositional reasoning in this complex setting. This is achieved, in part, by the use of explicit fixed point ordinal approximations, a ..."
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Cited by 11 (4 self)
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. We present a proof system for verifying CCS processes in the modal ¯calculus. Its novelty lies in the generality of the proof judgements allowing parametric and compositional reasoning in this complex setting. This is achieved, in part, by the use of explicit fixed point ordinal approximations, and in part by a complete separation, following an approach by Simpson, of rules concerning the logic from the rules encoding the operational semantics of the process language. 1 Introduction In a number of recent papers [14, 9] prooftheoretical frameworks for compositional verification have been put forward based on Gentzenstyle sequents of the shape \Gamma ` \Delta, where the components of \Gamma and \Delta are correctness assertions P : OE. Several programming or modelling languages have been considered, including CCS [3], the ßcalculus [2], CHOCS [1], general GSOSdefinable languages [9], and even a significant core fragment of a real programming language, Erlang [4]. An important ...
calculus with explicit points and approximations
 Previously appeared in Fixed Points in Computer Science, FICS '02
"... Abstract. We present a Gentzenstyle sequent calculus for program verication which accomodates both model checkinglike verication based on global state space exploration, and compositional reasoning. To handle the complexities arrising from the presence of xedpoint formulas, programs with dynamic ..."
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Cited by 10 (7 self)
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Abstract. We present a Gentzenstyle sequent calculus for program verication which accomodates both model checkinglike verication based on global state space exploration, and compositional reasoning. To handle the complexities arrising from the presence of xedpoint formulas, programs with dynamically evolving architecture, and cut rules we use transition assertions, and introduce xedpoint approximants explicitly into the assertion language. We address, in a gamebased manner, the semantical basis of this approach, as it applies to the entailment subproblem. Soundness and completeness results are obtained, and examples are shown illustrating some of the concepts. 1
Modal Characterization of Weak Bisimulation for Higherorder Processes
 IN TAPSOFT97, VOLUME 1214 OF LNCS
, 1996
"... Context bisimulation [13, 1] has become an important notion of behavioral equivalence for higherorder processes. Weak forms of context bisimulation are particularly interesting, because of their high level of abstraction. We present a modal logic for this setting and provide a characterization of a ..."
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Cited by 8 (0 self)
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Context bisimulation [13, 1] has become an important notion of behavioral equivalence for higherorder processes. Weak forms of context bisimulation are particularly interesting, because of their high level of abstraction. We present a modal logic for this setting and provide a characterization of a variant of weak context bisimulation on secondorder processes. We show how the logic permits compositional reasoning. In comparison to previous work by Amadio and Dam [2] on the strong case, our modal logic supports derived operators through a complete duality and thus constitutes an appealing extension of HennessyMilner logic.
µCalculus with Explicit Points and Approximations
, 2000
"... We present a Gentzenstyle sequent calculus for program verification which accomodates both model checkinglike verification based on global state space exploration, and compositional reasoning. To handle the complexities arrising from the presence of fixedpoint formulas, programs with dynamically ..."
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Cited by 6 (2 self)
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We present a Gentzenstyle sequent calculus for program verification which accomodates both model checkinglike verification based on global state space exploration, and compositional reasoning. To handle the complexities arrising from the presence of fixedpoint formulas, programs with dynamically evolving architecture, and cut rules we use transition assertions, and introduce fixedpoint approximants explicitly into the assertion language. We address, in a gamebased manner, the semantical basis of this approach, as it applies to the entailment subproblem. Soundness and completeness results are obtained, and examples are shown illustrating some of the concepts.
Firstorder reasoning for higherorder concurrency
, 2009
"... By combining and simplifying two of the most prominent theories for HOπ of Sangiorgi et al. and Jeffrey and Rathke [15, 4], we present an effective firstorder theory for a higherorder picalculus. There are two significant aspects to our theory. The first is that higherorder inputs are treated in ..."
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Cited by 4 (2 self)
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By combining and simplifying two of the most prominent theories for HOπ of Sangiorgi et al. and Jeffrey and Rathke [15, 4], we present an effective firstorder theory for a higherorder picalculus. There are two significant aspects to our theory. The first is that higherorder inputs are treated in a firstorder manner, hence eliminating the need to reason about arbitrarily complicated higherorder contexts, or to use upto context techniques, when establishing equivalences between processes. The second is that we use augmented processes to record directly the knowledge of the observer. This has the benefit of making ordinary firstorder weak bisimulation fully abstract w.r.t. contextual equivalence. It also simplifies the handling of names, giving rise to a truly propositional HennessyMilner characterisation of higherorder contextual equivalence. Furthermore, we illustrate the simplicity of our approach in proving several interesting equivalences by exhibiting firstorder witness weak bisimulations, and inequivalences by using the propositional HennessyMilner Logic. Finally we show that contextual equivalence
On the Bisimulation Theory and Axiomatization of Higherorder Process Calculi
"... Higherorder process calculi, for its abstraction capability and theoretical significance, have constantly been receiving much attention in the field of process calculi, and stand as a mathematical tool for describing and analyzing mobile systems with dynamically changing interconnection structures ..."
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Higherorder process calculi, for its abstraction capability and theoretical significance, have constantly been receiving much attention in the field of process calculi, and stand as a mathematical tool for describing and analyzing mobile systems with dynamically changing interconnection structures. In this thesis we contribute to the higherorder paradigm in several aspects. • Higherorder πcalculus with mismatch: the bisimulation theory. Linear fragment of higherorder πcalculus with mismatch: the axiomatization. The problem of the axiomatization of higherorder process calculi, such as higherorder πcalculus, is always a nontrivial one. However, it is important, both in theory and practice, to be able to decide whether two higherorder processes are equivalent with respect to some bisimulation, which needs an algorithm that can effectively analyze and give an answer efficiently. We further the available work by considering the higherorder πcalculus with mismatch, which is a useful operator in bisimulation theory and especially the axiomatization, from algorithmic point of view. We first formulate the bisimulation theory, where the bisimulation we define is called open weak higherorder bisimulation, which is a nondelayed
A synergy between modelchecking and type inference for the verification of valuepassing higherorder processes
 In Proceedings of AMAST’98
, 1999
"... Abstract. In this paper, we present a formal verification framework for higherorder valuepassing process algebra. This framework stems from an established synergy between type inference and modelchecking. The language considered here is based on a sugared version of an implicitly typed λcalculus ..."
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Abstract. In this paper, we present a formal verification framework for higherorder valuepassing process algebra. This framework stems from an established synergy between type inference and modelchecking. The language considered here is based on a sugared version of an implicitly typed λcalculus extended with higherorder synchronous concurrency primitives. First, we endow such a syntax with a semantic theory made of a static semantics together with a dynamic semantics. The static semantics consists of an annotated type system. The dynamic semantics is operational and comes as a twolayered labeled transition system. The dynamic semantics is abstracted into a transitional semantics so as to make finite some infinitestate processes. We describe the syntax and the semantics of a verification logic that allows one to specify properties. The logic is an extension of the modal µcalculus for handling higherorder processes, valuepassing and return of results. 1
Symbolic Bisimulation for a HigherOrder Distributed Language with Passivation?
"... Abstract. We study the behavioural theory of a higherorder distributed calculus with private names and locations that can be passivated. For this language, we present a novel Labelled Transition System where higherorder inputs are symbolic agents that can perform a limited number of transitions, c ..."
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Abstract. We study the behavioural theory of a higherorder distributed calculus with private names and locations that can be passivated. For this language, we present a novel Labelled Transition System where higherorder inputs are symbolic agents that can perform a limited number of transitions, capturing the nature of passivation. Standard firstorder weak bisimulation over this LTS coincides with contextual equivalence, and provides the first useful proof technique without a universal quantification over contexts for an intricate distributed language. 1