A characterization of stable models using a non-monotonic operator

Stable models seem to be a natural way to describe the beliefs of a rational agent How ever the de nition of stable models itself is not constructive It is therefore interesting to nd a constructive characterization of stable models using a xpoint construction The op erator we de ne is based on the work of among others F Fages For this operator every total stable model of a general logic program will coincide with the limit of some in nite sequence of interpretations generated by it Moreover the set of all stable models will coin cide with certain interpretations in these sequences Furthermore we will characterize the least xpoint of the Fitting operator and the well founded model using our operator Mathematical Subject Classi cation N CR Classi cation D F I