ptimally Efficient Inference Syste

This paper describes a knowledge representa-tion and reasoning system that performs a lim-ited but interesting class of inferences over a restricted class of first-order sentences with op-timal eticiency. The proposed system can an-swer yes-no as well as w/z-queries in time that is only proportional to the Zength of the short-est derivation of the query and is independent of the size of the knowledge base. This work suggests that the expressiveness and the infer-ential ability of a representation and reasoning systems may be limited in unusual ways to ar-rive at extremely efficient yet fairly powerful knowledge based systems