Embedding minimal knowledge into autoepistemic logic [chapter]

Riccardo Rosati
1997 Lecture Notes in Computer Science  
We investigate the epistemological properties of MKNF, Lifschitz's logic of minimal knowledge and negation as failure. In particular, we show that the expressive power of MKNF is equivalent to Moore's autoepistemic logic (AEL), by de ning an embedding of MKNF into AEL and vice versa. We also prove that the negation as failure modality not of MKNF exactly corresponds to the negative introspection operator in AEL. The two previous results imply that MKNF's minimal knowledge modality K can be
more » ... sented by means of negation as failure not, i.e. MKNF theories admit an equivalent representation in terms of unimodal theories using the not operator only. This in turn implies that negation as failure is \more expressive" than minimal knowledge.
doi:10.1007/3-540-63576-9_111 fatcat:qb6oht2hrrcilhrzqxyxr74ezy