Columbia President Grayson Kirk last night agreed to set up a tripartite commission of students, faculty, and administration to settle the week-long sit-in at the university.

Kirk submitted to the request of a 200-member ad hoc faculty committee, generally sympathetic with the student demonstrators, and also agreed to let faculty choose the student members of the commission.

Mark Rudd, chairman of Columbia's Students for a Democratic Society, speaking for the 500 to 600 rebels, has already said he will not accept a tripartite commission. Before students leave the five buildings they now hold, they must be guaranteed amnesty, Rudd said.

Earlier yesterday, a group of 80 Negro and white students, sympathetic with the student rebels, nearly broke through a blockade around Low Library in an effort to bring food to students entrenched in Kirk's offices inside.

Yelling "black power" and "food power," the sympathizers rushed 200 members of the anti-sit-in "majority coalition," who stationed themselves around the large colonaded library Sunday night in an attempt to starve out the demonstrators.

Fistfights broke out, but no one was injured. The sympathizers, who failed to breech the line, then began throwing food up to demonstrators standing on a ledge outside the second-floor library windows.

Sources at Columbia say they are certain that classes will be cancelled today, although no official announcement was to have been made until 6 a.m. this morning. Demonstrators interpret cancellation as a sign the university is not yet willing to call in police to remove them from the buildings.

Seize Hall

Meanwhile, 300 non-demonstrating students seized a sixth building, Uris Hall, saying they wanted to keep it out of the hands of rebels who might want to shut it down.

The ad hoc committee, which recommended the tripartite commission, called its plan "the last possibility of a peaceful settlement."

The committee had said that if Kirk did not accept the plan, and if police are brought in, some of its members would physically oppose the police. Others threatened to resign.

The 200 committee members represent all teaching ranks--from instructor through full professor. On Sunday, a meeting of all tenured Columbia professors approved their request for the commission.

Also approved at that meeting was a resolution that apparently assures no demonstrators will be expelled. The resolution asks for uniform punishment for all the students. "How could you expel several hundred students?" said Seymour Melman, professor of Industrial Engineering.

The demonstrators Sunday told the ad hoc committee to "stop trying to perform a mediating function . . . and take a political position" in favor of the demands including the general amnesty.

If the student rebels still refuse to leave the buildings after the latest Kirk announcement, they will lose the support of the ad hoc committee, and probably the support of large numbers of more moderate sympathizers as well.