He was an associate professor from 1977 to 1980 and became the Ray Ethan Torrey Professor in 1989 and the Constantine J. Gilgut Professor in 1998 .
An associate professor from 1977 to 1980 is a professor from 1980 - 1989 .
He was an associate professor from 1977 to 1980 , a professor from 1980 - 1989 , and became the Ray Ethan Torrey Professor in 1989 and the Constantine J. Gilgut Professor in 1998 .