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- Haykal Tej, Burkhart Wolff
- FME
- 1997

We present a failure-divergence model for CSP following the concepts of [BR 85]. Its formal representation within higher order logic in the theorem prover Isabelle/HOL [Pau 94] revealed an error in the basic definition of CSP concerning the treatment of the termination symbol tick. A corrected model has been formally proven consistent with Isabelle/HOL.… (More)

- David Aspinall, Christoph Lüth, Burkhart Wolff
- MKM
- 2005

Recently, significant advances have been made in formalised mathematical texts for large, demanding proofs. But although such large developments are possible, they still take an inordinate amount of effort and time, and there is a significant gap between the resulting formalised machine-checkable proof scripts and the corresponding human-readable… (More)

- Kolyang, Thomas Santen, Burkhart Wolff
- TPHOLs
- 1996

We present a semantic representation of the core concepts of the specification language Z in higher-order logic. Although it is a "shallow embedding" like the one presented by Bowen and Gordon, our representation preserves the structure of a Z specification and avoids expanding Z schemas. The representation is implemented in the higherorder logic instance… (More)

- Achim D. Brucker, Burkhart Wolff
- UML
- 2002

Based on experiences gained from an embedding of the Object Constraint Language (OCL) in higher-order logic [1], we explore several key issues of the design of a formal semantics of the OCL. These issues comprise the question of the interpretation of invariants, preand postconditions, an executable sub-language and the possibilities of refinement notions. A… (More)

- Achim D. Brucker, Burkhart Wolff
- FASE
- 2008

We present the theorem proving environment HOL-OCL that is integrated in a Model-driven Engineering (MDE) framework. HOL-OCL allows to reason over UML class models annotated with OCL specifications. Thus, HOL-OCL strengthens a crucial part of the UML to an objectoriented formal method. HOL-OCL provides several derived proof calculi that allow for formal… (More)

- Achim D. Brucker, Lukas Brügger, Burkhart Wolff
- TestCom/FATES
- 2008

Firewalls are a cornerstone of todays security infrastructure for networks. Their configuration, implementing a firewall policy, is inherently complex, hard to understand, and difficult to validate. We present a substantial case study performed with the model-based testing tool HOL-TestGen. Based on a formal model of firewalls and their policies in… (More)

- Achim D. Brucker, Burkhart Wolff
- Acta Informatica
- 2009

We present a formal semantics for an object-oriented specification language. The formal semantics is presented as a conservative shallow embedding in Isabelle/hol and the language is oriented towards ocl formulae in the context of uml class diagrams. On this basis, we formally derive several equational and tableaux calculi, which form the basis of an… (More)

The Circus specification language combines elements for complex data and behavior specifications, using an integration of Z and CSP with a refinement calculus. Its semantics is based on Hoare and He’s unifying theories of programming (UTP). We develop a machine-checked, formal semantics based on a “shallow embedding” of Circus in Isabelle/UTP (our semantic… (More)

- Achim D. Brucker, Matthias P. Krieger, Burkhart Wolff
- MoDELS Workshops
- 2009

From its beginnings, OCL is based on a strict semantics for undefinedness, with the exception of the logical connectives of type Boolean that constitute a three-valued propositional logic. Recent versions of the OCL standard added a second exception element, which, similar to the null references in object-oriented programming languages, is given a… (More)

- Achim D. Brucker, Lukas Brügger, Burkhart Wolff
- ICTAC
- 2013

The HOL-TestGen environment is conceived as a system for modeling and semi-automated test generation with an emphasis on expressive power and generality. However, its underlying technical framework Isabelle/HOL supports the customization as well as the development of highly automated add-ons working in specific application domains. In this paper, we present… (More)