Reductions to Sets of Low Information Content (extended Abstract)

*Department of Computer Science and Engineering, Indian Institute of Technology, DeLhi, New Delhi 110016, India. Work done while visiting Unlversit~/t Ulm. Supported in part by an Alexander von Humboldt postdoctoral research fellowship. IDepartment of Computer Science, University of Rochester, Rochester, NY 14627, USA. Supported in part by the National Science Foundation under research grant CCR-8957604. t Abteilung ffir Theoretische Informatik, Universit/~t Uhn, Oberer Eselsberg~ D-W-7900 Uhn, Germany. Supported in part by the DAAD through Acciones Integradas 1991, 313-AI-e-es/zk. w of Software (L.S.I.), Universitat Polit~cnica de Catalunya, Pau Gargallo 5, E-08028 Barcelona, Spain. Work supported in part by ESPRIT-II Basic Research Actions Program of the EC under Contract No. 3075 (project ALCOM) and by the DAAD through Aceiones Integradas 1991, 313-AI-e-es/zk. 82 of Computer Science and Information Mathematics, University of ElectroCommmfications, 1-5-1, Chofngaoka, Chofu-si, Tokyo 182, Japan. Work done in part while visiting SUNY-Buffalo. Supported in part by the National Science Foundation under research grant CCR9002292. //Dipartimento Di Matematica, Unlversits degli Studi di Roma, "La Sapienza," 00198 Rome, Italy. Work done in part while visiting the University of Rochester. Supported in part by Ministero della Pubblica Istruzione through "Progetto 40%: Algoritmi~ Modelli di Calcolo e Strutture Informative." **Abteilung ffir Theoretische Informatik, Universit~t Uhn, Oberer Eselsberg, D-W-7900 Ulm, Germany. Work done in part while visiting the University of Rochester. Supported in part by a DFG Post-doctoral Stipend and by the DAAD through Acciones Integradas 1991, 313-AI-e-es/zk.