April 6, 1981

A research group's findings that the United States could eliminate oil imports by improving energy efficiency have stirred considerable debate. The Energy Productivity Center of the Mellon Institute said in an unpublished study that the United States could eliminate oil imports by the year 2000, and save billions of dollars, by improving the efficiency of the equipment used to convert fuels to energy. ''We don't see any energy scarcity in our projections,'' said Roger Sant, director of the Washington-area research organization. The study calculates that the United States could cut the amount of money it pays for foreign oil from about $80 billion in 1980 to an average of $15 billion annually in the 1990's, to nothing at all after the year 2000.

The Art People column in Weekend on Friday incorrectly reported the time of a scheduled memorial service for the art dealer Julien Levy at the Cooper Union, Eighth Street and Astor Place. It will be held at 4 P.M. on Friday, April 24.

MILWAUKEE LINGERING near the foul line, Bob Lanier had vaguely heard his name being called. The Milwaukee Bucks' center - a striking, bearded man, 6 feet 11 inches tall, broad as Buddha - looked up. Quinn Buckner, a Bucks guard, was dribbling the ball hard with one hand and pointing with the other. ''Over there,'' shouted Buckner, who had called a play. Lanier snapped out of his reverie and moved across the gleaming floor of Milwaukee Arena, and planted a pick to set up the play; he was back in the game.

An outsized mouthful of pearly white teeth gleams from the magazine page. ''Introducing Advanced Formula Crest,'' the advertisement declares. ''Now, get fewer cavities with Crest than you ever got before.'' In a recent spate of television commercials, ''what's new'' at the neighborhood drugstore turns out to be ''new improved Colgate,'' with a ''100 percent pure'' mint taste. ''Mmmmmm,'' exclaims the customer. ''Colgate, better than ever.''

Leonid I. Brezhnev, the Soviet leader, flew to Prague today amid intense speculation here and in Eastern Europe that a decision by Moscow on whether to intervene in Poland would come in the next few days. Mr. Brezhnev was met at the airport by Gustav Husak, the leader of the Czechoslovak Communist Party, and the two men met again later to exchange ''views on some international problems,'' according to the Czechoslovak press agency, CTK. In Washington, officials said that President Reagan had sent a strongly worded message to Mr. Brezhnev on Friday that was intended to underscore the seriousness with which the United States viewed Soviet military moves in and around Poland. (Page A10.)