An engine for logic program analysis

An engine that is based on unfolding of semantic equations is presented. A main advantage of the unfolding engine is a uniform treatment of structural information in a program. In particular, reasoning about partially instantiated structures, an area where traditional algorithms have been weak, is greatly enhanced. It is shown that the engine is uniformly more accurate than the standard engine in the sense that, given an abstract domain, its output, for any program is more accurate than that of the standard engine.<>