This paper describes a framework, based on Abstract Interpretation, for creating abstractions for model-checking. Specifically, we study how to abstract models of µcalculus and systematically derive abstractions that are constructive, sound, and precise, and apply them to abstracting Kripke structures. The overall approach is based on the use of bilattices to represent partial and inconsistent information. 1

This paper investigates both the precision and the model checking efficiency of abstract models designed to preserve branching time logics w.r.t. a 3-valued semantics. Current abstract models use ordinary transitions to over approximate the concrete transitions, while they use hyper transitions to under approximate the concrete transitions. In this work we refer to precision measured w.r.t. the choice of abstract states, independently of the formalism used to describe abstract models. We show that current abstract models do not allow maximal precision. We suggest a new class of models and a construction of an abstract model which is most precise w.r.t. any choice of abstract states. As before, the construction of such models might involve an exponential blowup, which is inherent by the use of hyper transitions. We therefore suggest an efficient algorithm in which the abstract model is constructed during model checking, by need. Our algorithm achieves maximal precision w.r.t. the given property while remaining quadratic in the number of abstract states. To complete the picture, we incorporate it into an abstraction-refinement framework. 1.

Abstract. We study the underapproximation of the predicate transformers used to give semantics to the modalities in dynamic and temporal logic. Because predicate transformers operate on state sets, we define appropriate powerdomains for sound approximation. We study four such domains — two are based on “set inclusion ” approximation, and two are based on “quantification ” approximation — and we apply the domains to synthesize the most precise, underapproximating �pre and pre transformers, in the latter case, introducing a focus operation. We also show why the expected abstractions of post and �post are unsound, and we use the powerdomains to guide us to correct, sound underapproximations. 1

Abstract. Standard abstract model checking relies on abstract Kripke structures which approximate the concrete model by gluing together indistinguishable states. Strong preservation for a specification language L encodes the equivalence of concrete and abstract model checking of formulas in L. Abstract interpretation allows to design abstract models which are more general than abstract Kripke structures. In this paper we show how abstract interpretation-based models can be exploited in order to specify a general strongly preserving abstract model checking framework. This is shown in particular for specification languages including standard temporal operators which admit a characterization as least/greatest fixpoints, as e.g. standard “Finally”, “Globally”, “Until ” and “Release ” modalities. 1