S. Mac Lane, 95; Pioneering U.S. Mathematician

Saunders Mac Lane, one of the country’s leading mathematicians and a professor at the University of Chicago for nearly four decades, has died. He was 95.

Mac Lane died April 14 in San Francisco after a long illness, according to the university.

In a landmark paper he co-wrote with Samuel Eilenberg in 1945, Mac Lane developed new ways of thinking about mathematics, introducing what are known as “categories,” “functors” and “natural transformations,” University of Chicago math professor Peter May said in a statement.

“A very great deal of mathematics since then would quite literally have been unthinkable without that language,” the statement said.

Mac Lane received the nation’s highest award for scientific achievement, the National Medal of Sciences, in 1989.

Born in Norwich, Conn., he earned a bachelor’s degree from Yale University and a master’s from the University of Chicago. He received a doctorate in 1934 from the Mathematics Institute in Gottingen, Germany.

Mac Lane began teaching math at the University of Chicago in 1947, retiring in 1982.

He wrote or co-wrote six books, including “A Survey of Modern Algebra,” which became a leading text in the field.