Marina Ratner

Marina Evseevna Ratner (; October 30, 1938 – July 7, 2017) was a Russian-American professor of mathematics at the University of California, Berkeley. She worked in ergodic theory. She was born in Moscow, and of Jewish descent.
Around 1990, she proved a group of major theorems concerning unipotent flows on homogeneous spaces, known as Ratner's theorems. Ratner was elected to the American Academy of Arts and Sciences in 1992, awarded the Ostrowski Prize in 1993 and elected to the National Academy of Sciences the same year. In 1994, she was awarded the John J. Carty Award from the National Academy of Sciences.
Ratner died in Berkeley, California on July 7, 2017 of a stroke at the age of 78.