Off-line compilation of logic grammars using Magic allows an incorporation of
filtering into the logic underlying the grammar. The explicit definite clause
characterization of filtering resulting from Magic compilation allows processor
independent and logically clean optimizations of dynamic bottom-up processing
with respect to goal-directedness. Two filter optimizations based on the
program transformation technique of Unfolding are discussed which are of
practical and theoretical interest.Comment: 8 pages LaTeX (uses aclap.sty