Christoph Lüth

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When autonomous robots begin to share the human living and working spaces, safety becomes paramount. It is legally required that the safety of such systems is ensured, e. g. by certification according to relevant standards such as IEC 61508. However, such safety considerations are usually not addressed in academic robotics. In this paper we report on one(More)
Monads are a useful abstraction of computation, as they model diverse computational effects such as stateful computations, exceptions and I/O in a uniform manner. Their potential to provide both a modular semantics and a modular programming style was soon recognised. However, in general, monads proved difficult to compose and so research focused on special(More)
This paper introduces a semantics for rewriting that is independent of the data being rewritten and which, nevertheless, models key concepts such as substitution which are central to rewriting algorithms. We demonstrate the naturalness of this construction by showing how it mirrors the usual treatment of algebraic theories as coequalizers of monads. We also(More)
Whilst the relationship between initial algebras and monads is well understood, the relationship between final coalgebras and comonads is less well explored. This paper shows that the problem is more subtle than might appear at first glance: final coalgebras can form monads just as easily as comonads, and, dually, initial algebras form both monads and(More)
We introduce and study a tactic language, Hitac, for constructing hierarchical proofs, known as hiproofs. The idea of hiproofs is to superimpose a labelled hierarchical nesting on an ordinary proof tree. The labels and nesting are used to describe the organisation of the proof, typically relating to its construction process. This can be useful for(More)
The aim of the MMiSS project is the construction of a multimedia Internet-based adaptive educational system. Its content will initially cover a curriculum in the area of Safe and Secure Systems. Traditional teaching materials (slides, handouts, annotated course material, assignments, and so on) are to be converted into a new hypermedia format, integrated(More)
The design of theorem provers, especially in the LCF-prover family, has strongly profited from functional programming. This paper attempts to develop a metaphor suited to visualize the LCF-style prover design, and a methodology for the implementation of graphical user interfaces for these provers and encapsulations of formal methods. In this problem domain,(More)