Today's 17th game of the Garry Kasparov-Anatoly Karpov world chess championship has been postponed until Wednesday at Kasparov's request. The two Soviet grandmasters are scheduled to resume the 16th game on Tuesday. That game was contested for five hours Saturday and nearly six hours Sunday without a result after 88 moves. Through the 15 completed games, the players are tied with 7.5 points each. They have had three draws in the French portion of the championship. They had 10 draws in the 12 games played at New York between Oct. 8 and Nov. 7. The first player to reach 12.5 points wins the championship, but Kasparov would retain the title in the event of a 12-12 draw. Each player is allowed to request up to three postponements during the championship. The postponement requested by Kasparov today was his second. Karpov has used one timeout.