Information Systems Dept
Technical University of Vienna
A-1040 Vienna
eiter@kr.tuwien.ac.at
Information Systems Dept
Technical University of Vienna
A-1040 Vienna
leone@dbai.tuwien.ac.at
DFKI GmbH
PF 15 11 50, D-66041 Saarbrücken
David.Pearce@dfki.de
Generalising the ideas of LRS97 we define a simple extension of the notion of unfounded set, called assumption set, that applies to disjunctive logic programs with strong negation. We show that assumption-free interpretations of such extended logic programs coincide with equilibrium models in the sense of Pe97 and hence with the answer sets of GL90, GL91.