Evolutional tableau method for temporal logic specifications

Presents a new consistency checking method for temporal logic specifications. The new method verifies the consistency of a whole specification by using a tableau graph constructed from tableau graphs obtained in the verifications of partial specifications. The new method is applicable not only to on-the-fly verification but also to compositional verification. On-the-fly verification is verification that proceeds as a specification is evolved; compositional verification is verification constructed by merging modular verifications. By verifying a specification at each step of its refinement, we can make the specification evolution process efficient. A tableau graph constructed by a traditional tableau method does not suit reuse. The traditional tableau method has two phases: a tableau graph construction phase and an eventuality checking phase. It is difficult to reflect the results of the eventuality checking on the tableau graph because there is no suitable substructure which can store the results. For that reason, it is necessary to check eventuality formulae repeatedly on the reuse of the tableau graphs. A new tableau graph introduced in this paper has a new structure and is obtained by piling up tableau graphs of subformulae. In this new structure, the checked results of eventuality checking are encoded. Therefore, all the results of the verification in each step can be reused for constructing the verification for a whole specification.