Elmer Beaumont Tolsted, 72, mathematics professor who was recruited to teach at Pomona College by a colleague who wanted him to join his chamber music group. Tolsted, an accomplished cellist, taught at Claremont from 1947 to 1982 and continued teaching part time until his death. Educated at the University of Chicago and Brown University, he studied in England as a Fulbright scholar and returned twice to do research. He began studying the violoncello at age 11, and as a Claremont professor performed recitals in many parts of Southern California, Chicago, New York, Aspen, Zurich, Tokyo, London and Paris. On Tuesday in Champaign, Ill., of heart failure.