Henning Christiansen

Learn More
A class of Probabilistic Abductive Logic Programs (PALPs) is introduced and an implementation is developed in CHR for solving abductive problems, providing minimal explanations with their probabilities. Both all-explanations and most-probable-explanations versions are given. Compared with other probabilistic versions of abductive logic programming , the(More)
We present HYPROLOG, a novel integration of Prolog with assumptions and abduction which is implemented in and partly borrows syntax from Constraint Handling Rules (CHR) for integrity constraints. Assumptions are a mechanism inspired by linear logic and taken over from Assumption Grammars. The language shows a novel flexibility in the interaction between the(More)
Integrity constraint and abduction are important in query-answering systems for enhanced query processing and for expressing knowledge in databases. A straightforward characterization of the two is given in a subset of the language CHR ¤ , originally intended for writing constraint solvers to be applied for CLP languages. This subset has a strikingly simple(More)
This paper is a comment on two recent contributions to Sigplan Notices. In his paperC QThe static semantics !leRC no. 25/4C Brian Meek discusses the relevance of the notion of Qstatic semanticsR. The relation between a variable's declaration and the restrictions on its useC for exampleC is usually classi!ed as static semantics. Meek !nds the designation(More)
A grammar formalism based upon CHR is proposed analogously to the way Definite Clause Grammars are defined and implemented on top of Prolog. These grammars execute as robust bottom-up parsers with an inherent treatment of ambiguity and a high flexibility to model various linguistic phenomena. The formalism extends previous logic programming based grammars(More)