It is well known that interpolation properties of logics underlying specification formalisms play an important role in the study of structured specifications, they have also many other useful logical consequences. In this paper, we solve the interpolation problem for Grothendieck institutions which have recently emerged as an important mathematical structure underlying heterogenous multi-logic specification. Our main result can be used in the applications in several different ways. It can be used to establish interpolation properties for multi-logic Grothendieck institutions, but also to lift interpolation properties from unsorted logics to their many sorted variants. The importance of the latter resides in the fact that, unlike other structural properties of logics, many sorted interpolation is a non-trivial generalisation of unsorted interpolation. The concepts, results, and the applications discussed in this paper are illustrated with several examples from conventional logic and algebraic specification theory.

In order to obtain a semantic foundation for heterogeneous specification, we extend Diaconescu's morphism-based Grothendieck institutions to the case of comorphisms. This is not just a dualization, because we obtain more general results, especially concerning amalgamation properties. We also introduce a proof calculus for structured heterogeneous speci cations and study its soundness and completeness (where amalgamation properties play a r^ole for obtaining the latter).

The UniForM Workbench supports combination of Formal Methods (on a solid logical foundation), provides tools for the development of hybrid, real-time or reactive systems, transformation, verification, validation and testing. Moreover, it...

For the recently developed specification language Casl, there exist two different kinds of proof support: while HOL-Casl has its strength in proofs about specifications in-the-small, Maya has been designed for management of proofs in (Casl) specifications in-the-large, within an evolutionary formal software development process involving changes of specifications. In this work, we discuss our integration of HOL-Casl and Maya into a powerful system providing tool support for Casl, which will also serve as a basis for the integration of further proof tools.

. The paper addresses important problems of building complex logical systems and their representations in universal logics in a systematic way. We adopt the model-theoretic view of logic as captured in the notions of institution and of parchment (an algebraic way of presenting institutions). We propose a new, modified notion of parchment together with parchment morphisms and representations. In contrast to the original parchment definition and our earlier work, in model-theoretic parchments introduced here the universal semantic structure is distributed over individual signatures and models. We lift formal properties of the categories of institutions and their representations to this level: the category of model-theoretic parchments is complete, and their representations may be put together using categorical limits as well. However, model-theoretic parchments provide a more adequate framework for systematic combination of logical systems than institutions. We indicate how the necessar...

CASL, the common algebraic specification language, has been developed as a language that subsumes many previous algebraic specification frameworks and also provides tool interoperability. CASL is a complex language with a complete formal semantics. It is therefore a challenge to build good tools for CASL. In this work, we present and discuss the Bremen HOL-CASL system, which provides parsing, static checking, conversion to LaTeX and theorem proving for CASL specifications. To make tool construction manageable, we have followed some guidelines: re-use of existing tools, interoperability of tools developed at different sites, and construction of generic tools that can be used for several languages. We describe the structure of and the experiences with our tool and discuss how the guidelines work in practice.

This paper studies the composition of modules that can hide information, over a very general class of logical systems called inclusive institutions. Two semantics are given for composition of such modules using five familiar operations, and a property called conservativity is shown necessary and sufficient for these semantics to agree. The first semantics extracts the visible properties of the result of composing the visible and hidden parts of modules, while the second uses only the visible properties of the components; the semantics agree when the visible consequences of hidden information are enough to determine the result of the composition. A number of "laws of software composition" are proved relating the composition operations. Inclusive institutions simplify many proofs.

Categorial characterizations are given of both unconstrained and constrained fibring of Hibert calculi and interpretation systems for languages with variables, terms, variable binding operators and modal like operators. Some preliminary transference results are established. A brief comparison with model theoretic parchments is included.

Abstract. Development graphs are a tool for dealing with structured specifications in a formal program development in order to ease the management of change and reusing proofs. Often, different aspects of a software system have to be specified in different logics, since the construction of a huge logic covering all needed features would be too complex to be feasible. Therefore, we introduce heterogeneous development graphs as a means to cope with heterogeneous specifications. We cover both the semantics and the proof theory of heterogeneous development graphs. A proof calculus can be obtained either by combining proof calculi for the individual logics, or by representing these in some “universal ” logic like higher-order logic in a coherent way and then “borrowing” its calculus for the heterogeneous language. 1

. Several mechanisms for combining logics have appeared in the literature. Synchronization is one of the simplest: the language of the combined logic is the disjoint union of the given languages, but the class of models of the resulting logic is a subset of the cartesian product of the given classes of models (the interaction between the two logics is imposed by constraining the class of pairs of models). Herein, we give both a model-theoretic and a proof-theoretic account of synchronization as a categorial construction (using coproducts and cocartesian liftings) . We also prove that soundness is preserved by possibly constrained synchronization and state sufficient conditions for preservation of model existence and strong completeness. We provide an application to the combination of dynamic logic and linear temporal logic. Keywords: combination of logics, synchronization of logics, model existence, completeness, dynamic logic, temporal logic. 1 Introduction There has been a recent g...