Dynamic Dependency Pairs for Algebraic Functional Systems

We extend the higher-order termination method of dynamic dependency pairs to Algebraic Functional Systems (AFSs). In this setting, simply typed lambda-terms with algebraic reduction and separate {\beta}-steps are considered. For left-linear AFSs, the method is shown to be complete. For so-called local AFSs we define a variation of usable rules and an extension of argument filterings. All these techniques have been implemented in the higher-order termination tool WANDA

Translating logic programs into conditional rewriting systems

In this paper a translation from a subclass of logic programs consisting of the simply moded logic programs into rewriting systems is defined. In these rewriting systems conditions and explicit substitutions may be present. We argue that our translation is more natural than previously studied ones and establish a result showing its correctness

On normalisation

Using a characterisation of strongly normalising $lambda$-terms, we give new and simple proofs of the following: all developments and superdevelopments are finite, a certain rewrite strategy is perpetual, a certain rewrite strategy is maximal and thus perpetual, simply typed $lambda$-calculus is strongly normalising

On normalisation

Using a characterisation of strongly normalising $lambda$-terms, we give new and simple proofs of the following: all developments and superdevelopments are finite, a certain rewrite strategy is perpetual, a certain rewrite strategy is maximal and thus perpetual, simply typed $lambda$-calculus is strongly normalising

Weak orthogonality implies confluence: the higher-order case

In this paper we prove confluence for weakly orthogonal Higher-Order Rewriting Systems. This generalises all the known `confluence by orthogonality' results

Weak orthogonality implies confluence : the higher-order case

In this paper we prove confluence for weakly orthogonal Higher-Order Rewriting Systems. This generalises all the known `confluence by orthogonality' results

On the Existence of Universal Finite or Pushdown Automata

We investigate the (non)-existence of universal automata for some classes of automata, such as finite automata and pushdown automata, and in particular the influence of the representation and encoding function. An alternative approach, using transition systems, is presented too.Comment: In Proceedings DCM 2011, arXiv:1207.6821. Sadly, Manfred Kudlek passed away June 18, 2012, before publication of this pape

Completeness of algebraic CPS simulations

The algebraic lambda calculus and the linear algebraic lambda calculus are two extensions of the classical lambda calculus with linear combinations of terms. They arise independently in distinct contexts: the former is a fragment of the differential lambda calculus, the latter is a candidate lambda calculus for quantum computation. They differ in the handling of application arguments and algebraic rules. The two languages can simulate each other using an algebraic extension of the well-known call-by-value and call-by-name CPS translations. These simulations are sound, in that they preserve reductions. In this paper, we prove that the simulations are actually complete, strengthening the connection between the two languages.Comment: In Proceedings DCM 2011, arXiv:1207.682