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外文会议>International Conference of B Users
>Interpreting Invariant Composition in the B Method Using the Spec# Ownership Relation: A Way to Explain and Relax B Restrictions
【24h】
Interpreting Invariant Composition in the B Method Using the Spec# Ownership Relation: A Way to Explain and Relax B Restrictions
In the B method, the invariant of a component cannot be violated outside its own operations. This approach has a great advantage: the users of a component can assume its invariant without having to prove it. But, B users must deal with important architecture restrictions that ensure the soundness of reasonings involving invariants. Moreover, understanding how these restrictions ensure soundness is not trivial. This paper studies a meta-model of invariant composition, inspired from the Spec# approach. Basically, in this model, invariant violations are monitored using ghost variables. The consistency of assumptions about invariants is controlled by very simple proof obligations. Hence, this model provides a simple framework to understand B composition rules and to study some conservative extensions of B authorizing more architectures and providing more control on components initialization.
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