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Comparison.

The chief distinction between the two specification approaches arises in the amount of information they require users to specify. Logic-based approaches support very loose specifications, as one is allowed to identify single properties that systems should have. Relational approaches require fairly complete specifications of required observable behavior; in this respect preorders generally allow looser specifications than equivalences, however. Behavioral relations provide support for step-wise refinement of systems as well as compositional approaches to analyzing system behavior, which temporal logics in general do not, since the specification and system notations differ.

Connections between the two approaches have also been explored. In particular, a temporal logic induces an equivalence on systems as follows: two system are equivalent if and only if they satisfy the same formulas. Using this framework, relationships between different linear- and branching-time logics and equivalences have been established.



Scott Smolka
Thu Aug 22 10:56:53 EDT 1996