DIMACS Challenge: Call for Preliminary Abstracts and Update Just a reminder that January 15, 1993 is the due date for abstracts to be reviewed. This date replaces the previously announced December 31, 1992 date. Please send the abstracts to challenge@dimacs.rutgers.edu. This message is being sent from a different account than normal. I have some worries that some of you have not been receiving announcements and updates before. If you have been on the mailing list since before December 1, and you have not been receiving the updates (there have been four in total), please 1) ftp to dimacs.rutgers.edu and look at the files in pub/challenge (the .UPD files are the various updates) to catch up, and 2) contact me (either at mt1w+@andrew.cmu.edu or challenge@dimacs.rutgers.edu) to let me know of the problem so our computer people can try to fix the glitches. If you need a bit more time to submit an abstract due to mailer failure, please let me know. Finally, our automatic mail server seems to be not working. If you do not have access to ftp and wish to have files sent by email, please write me directly and I will act as a (slightly slow) automatic mail server. Please use ftp if at all possible. I will announce when we have our mail server fixed again. New files at dimacs.rutgers.edu: graph/contributed/mannino/: Work from Carlo Mannino of the Universit\'a di Roma La Spienza. A joint paper with Antonio Sassano on an exact algorithm for stable sets. Thank you for your interest in the DIMACS Challenge. Mike Trick Challenge Coordinator