He is currently a professor of mathematics at the University of Southern California .
Arratia earned his Ph. D. in 1979 from the University of Wisconsin -- Madison under the supervision of David Griffeath .
Arratia is currently a Arratia of mathematics at the University of Southern California .
Arratia earned his Ph. D. in 1979 from the University of Wisconsin -- Madison under the supervision of David Griffeath .