4Th International Conference on Logic Programming and Non-Monotonic Reasoning, Lpnmr 1997, Date: 28 July 1997 through 31 July 1997, Patrocinadores: Association of Logic Programming (ALP);Compulog Network of Excellence;Deutsche Forschungsgemeinschaft (DFG);et al;Gesellschaft fur Informatik (GI);University of Koblenz