. We consider the problem of precisely de#ning UML active classes with an associated state chart. We are convinced that the #rst step to make UML precise is to #nd an underlying formal model for the systems modelled by UML. We argue that labelled transition systems are a sensible choice; indeed they have worked quite successfully for languages as Ada and Java. Moreover, we think that this modelization will help to understand the UML constructs and to improve their use in practice. Here we present the labelled transition system associated with an active class using the algebraic speci#cation language CASL. The task of making precise this fragment of UML raises many questions about both the #precise" meaning of some constructs and the soundness of some allowed combination of constructs. 1 Introduction The Uni#ed Modeling Language #UML# #11# is an industry standard language for specifying software systems. This language is unique and important for several reasons: # UML is an...

We study proof systems for reasoning about logical consequences and refinement of structured specifications, based on similar systems proposed earlier in the literature [ST 88, Wir 91]. Following Goguen and Burstall, the notion of an underlying logical system over which we build specifications is formalized as an institution and extended to a more general notion, called (D, T )-institution. We show that under simple assumptions (essentially: amalgamation and interpolation) the proposed proof systems are sound and complete. The completeness proofs are inspired by proofs due to M. V. Cengarle (see [Cen 94]) for specifications in first-order logic and the logical systems for reasoning about them. We then propose a methodology for reusing proof systems built over institutions rich enough to satisfy the properties required for the completeness results for specifications built over poorer institutions where these properties need not hold.

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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).

this paper we present Casl-Chart a formal visual specification language for reactive systems obtained by combining an already existing language for reactive systems, precisely the statecharts as supported by Statemate ([6, 7]), with an already existing language for the specification of data structures, precisely the algebraic specification language Casl ([12, 17])

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...

The aim of this chapter is to describe the integrated specification- and theorem proving environment of KIV. KIV is an advanced tool for developing high assurance systems. It supports: --- hierarchical formal specification of software and system designs --- specification of safety/security models --- proving properties of specifications --- modular implementation of specification components --- modular verification of implementations --- incremental verification and error correction --- reuse of specifications, proofs, and verified components KIV supports the entire design process from formal specifications to verified code. It supports functional as well as state-based modeling. KIV is ready for use, and has been tested in a number of indu...

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 presents a permissive subsorted partial logic used in the CoFI Algebraic Specification Language. In contrast to other ordersorted logics, subsorting is not modeled by set inclusions, but by injective embeddings allowing for more general models in which subtypes can have different data type representations. Furthermore, there are no restrictions like monotonicity, regularity or local filtration on signatures at all. Instead, the use of overloaded functions and predicates in formulae is required to be sufficiently disambiguated, such that all parses have the same semantics. An overload resolution algorithm is sketched. 1 Introduction During the past decades a large number of algebraic specification languages have been developed. The presence of so many similar specification languages with no common framework hinders the dissemination and application of research results in algebraic specification. In particular, it makes it difficult to produce educational material, to re-us...

Casl is an expressive language for the specification of functional requirements and modular design of software. It has been designed by CoFI, the international Common Framework Initiative for algebraic specification and development. It is based on a critical selection of features that have already been explored in various contexts, including subsorts, partial functions, first-order logic, and structured and architectural specifications. Casl should facilitate interoperability of many existing algebraic prototyping and verification tools.