Complex sentence: Born in Belgium, Stein graduated from Stuyvesant High School in 1949 and received a Ph.D. from the University of Chicago in 1955, under the direction of Antoni Zygmund.
Split into simpler sentences: Born in Belgium, Stein graduated from Stuyvesant High School in 1949. In 1955, Stein earned a Ph.D. from the University of Chicago under the direction of Antoni Zygmund.