A class of formulas called factored negation normal form is introduced. They are closely related to BDDs, but there is a DPLL-like tableau procedure for computing them that operates in PSPACE.Ordered factored negation normal form provides a canonical representation for any boolean function. Reduction strategies are developed that provide a unique reduced factored negation normal form. These com...

Defeasible logic is an important logic-programming based nonmonotonic reasoning formalism which has an eecient implementation. It makes use of facts, strict rules, defeasible rules, defeaters, and a superiority relation. Representation results are important because they can help the assimilation of a concept by connning attention to its critical aspects. In this paper we derive some representat...

Normal forms were introduced by Poincaré as a tool to integrate nonlinear systems; by now we know this is in general impossible, but it turned out that the usefulness of normal forms goes well beyond integrability. An introduction to normal forms is provided e.g. in [3, 5, 26, 41, 43, 47, 63]; see also [10, 33]. An introduction to normal forms for Hamiltonian systems is given in appendix 7 of [...

We continue here a study of properties of rewrite systems that are not necessarily terminating, but allow for infinite derivations that have a limit. In particular, we give algebraic semantics for theories described by such systems, consider sufficient completeness of hierarchical systems, suggest practical conditions for the existence of a limit and for its uniqueness, and extend the ideas to ...

We apply the PolyBoRi framework for Gröbner bases computations with Boolean polynomials to bit-valued problems from algebraic cryptanalysis and formal verification. First, we proposed zero-suppressed binary decision diagrams (ZDDs) as a suitable data structure for Boolean polynomials. Utilizing the advantages of ZDDs we develop new reduced normal form algorithms for linear lexicographical lead ...

The relationship and possible interplay between different knowledge representation and reasoning paradigms is a fundamental topic in artificial intelligence. For expressive knowledge representation for the Semantic Web, two different paradigms – namely Description Logics (DLs) and Logic Programming – are the two most successful approaches. A study of their exact relationships is thus paramount....

The conceptual separation between computation and coordination in distributed computing systems motivates the use of peculiar entities commonly called connectors, whose task is managing the interaction among distributed components. Different kinds of connectors exist in the literature at different levels of abstraction. We focus on a basic algebra of connectors which is expressive enough to mod...