Knowledge representation and reasoning in incomplete logic programming

The central research theme in logic programming is the development of a computer system in which the programmer can represent his knowledge on the problem domain in a declarative manner and which solves computational problems on the domain by means of domain independent procedures.

The thesis contains a number of contributions on the declarative and the procedural level. So far, an important problem of logic programming was that incomplete knowledge about the problem domain could not be described accurately. We show that the formalism of abductive logic programs is an expressive logic for the declarative specification of this form of knowledge. In the thesis we propose an intuitive interpretation for this formalism, we investigate the existing semantics and extend them.