Abstract. Heterogeneous specification becomes more and more important because complex systems are often specified using multiple viewpoints, involving multiple formalisms. Moreover, a formal software development process may lead to a change of formalism during the development. However, current research in integrated formal methods only deals with ad-hoc integrations of different formalisms. The heterogeneous tool set (Hets) is a parsing, static analysis and proof management tool combining various such tools for individual specification languages, thus providing a tool for heterogeneous multi-logic specification. Hets is based on a graph of logics and languages (formalized as so-called institutions), their tools, and their translations. This provides a clean semantics of heterogeneous specification, as well as a corresponding proof calculus. For proof management, the calculus of development graphs (known from other large-scale proof management systems) has been adapted to heterogeneous specification. Development graphs provide an overview of the (heterogeneous) specification module hierarchy and the current proof state, and thus may be used for monitoring the overall correctness of a heterogeneous development. 1

Colimits are a useful tool for the combination of specifications and logical theories. We generalize the notion of colimit to a heterogeneous multi-logic setting. For practically realistic cases, the notion has to be weakened. We describe an algorithm that approximates the weaker notion but obtains a colimit whenever possible. This algorithm is being implemented as part of the Heterogeneous Tool Set HETS.

Abstract not found

In the domain of qualitative constraint reasoning, a subfield of AI which has evolved in the past 25 years, a large number of calculi for efficient reasoning about spatial and temporal entities has been developed. Reasoning techniques developed for these constraint calculi typically rely on so-called composition tables of the calculus at hand, which allow for replacing semantic reasoning by symbolic operations. Often these composition tables are developed in a quite informal, pictorial manner and hence composition tables are prone to errors. In view of possible safety critical applications of qualitative calculi, however, it is desirable to formally verify these composition tables. In general, the verification of composition tables is a tedious task, in particular in cases where the semantics of the calculus depends on higher-order constructs such as sets. In this paper we address this problem by presenting a heterogeneous proof method that allows for combining a higherorder proof assistance system (such as Isabelle) with an automatic (first order) reasoner (such as SPASS or VAMPIRE). The benefit of this method is that the number of proof obligations that is to be proven interactively with a semi-automatic reasoner can be minimized to an acceptable level.

We introduce two institutions for the process algebra Csp, one for the traces model, and one for the stable failures model. The construction is generic and should be easily instantiated with further models. As a consequence, we can use structured specification constructs like renaming, hiding and parameterisation (that have been introduced over an arbitrary institution) also for Csp. With a small example we demonstrate that structuring indeed makes sense for Csp.

(the latter needs subscription to the mailing list)

(the latter needs subscription to the mailing list)

Abstract. We present the integration of refinement method of VSE verification tool, successfully used in industrial applications, in the Heterogeneous Tool Set HETS. The connection is done via introducing the dynamic logic underlying VSE and two logic translations in the logic graph of HETS. Thus the logic-independent layers of HETS are not modified and its proof management formalism can be applied to VSE specifications. 1

The central idea of the Heterogeneous Tool Set (HETS) is to provide a general framework for formal methods integration and proof management. One can think of HETS acting like a motherboard where different expansion cards can be plugged in, the expansion cards here being individual logics (with their analysis

Abstract. Maude modules can be understood as models that can be formally analyzed and verified with respect to different properties expressing various formal requirements. However, Maude lacks the formal tools to perform some of these analyses and thus they can only be done by hand. The Heterogeneous Tool Set Hets is an institution-based combination of different logics and corresponding rewriting, model checking and proof tools. We present in this paper an integration of Maude into Hets that allows to use the logics and tools already integrated in Hets with Maude specifications. To achieve such integration we have defined an institution for Maude based on preordered algebras and a comorphism between Maude and Casl, the central logic in Hets.