Loop Checking and the Wll-Founded Semantics

Using a calculus of goals, we define the success and failure of a goal for propositional programs in the presence of loop checking. The calculus is sound with respect to the well-founded semantics; for finite programs, it is also complete. A Prolog-style proof search strategy for a modification of this calculus provides a query evaluation algorithm for finite propositional programs under the well-founded semantics. This algorithm is implemented as a meta-interpreter.