A General First-Order Solution to the Ramification Problem

We present a combined solution to the frame and ramification problems that is independent of the underlying time structure. Indirect effects are expressed through ramification rules that are compiled into first-order effect axioms. To cope with the notorious problem of self-justifying cycles, we use techniques known from translations of normal logic programs to logical theories: cyclic fluent dependencies in the ramification rules are identified, and for each such loop, a loop formula is built into the effect axiom to guarantee proper treatment of circular causal dependencies.