Improving the Efficiency of Non-Deterministic Computations1 1Supported in part by NSF grants INT-9981317 and CCR-0110496 and by the Spanish Knowledge Society Foundation, the Spanish Research Funding Agency (CICYT) TIC 2001-2705-C03-01, by Acción Integrade Hispano-Italiana HI2000-0161, and the Valencian Research Council under grant GV01-424. | Publicación