October 30, 1938 - July 7, 2017

Marina Ratner grew up in a household with parents who were both scientists. She excelled in mathematics as a high school student, encouraged by one of her teachers. In 1956 she applied to enter Moscow State University, which had just recently opened its doors to Jewish students. She studied mostly mathematics with a bit of physics and the required Marxism and Communist Party history courses. She received her M.A. degree in 1961. She then went to work for Professor A. N. Kolmogorov in his applied statistics group and taught in his school for gifted high school students. During this time she also gave birth to her daughter.

In 1965 Ratner returned to Moscow State University, earning her Ph.D. in 1969 under the supervision of Yakov G. Sinai. Her thesis was on "Geodesic Flows on Unit Tangent Bundles of Compact Surfaces of Negative Curvature." For the next year she was an assistant at the High Technical Engineering School in Moscow, but was fired when she applied for a visa to emigrate to Israel. Ratner lived In Israel from 1971 to 1975, teaching as a lecturer at the Hebrew University of Jerusalem and the Pre-academic School of that university. In 1975 she was hired by the University of California at Berkeley as an acting assistant professor. She remained at Berkeley, rising to the rank of professor in 1982.

Ratner's main work has been in the area of ergodic theory, an area of
mathematics related to probability theory and statistics that originated in
the study of thermodynamics. In 1992 she was elected to the American
Academy of Arts and Sciences, and the following year was elected to
the National Academy of Sciences (NAS). In 1994 the NAS awarded her the
John. J. Carty Award for the Advancement of Science for her noteworthy and
distinguished accomplishments in mathematics, in particular, her "striking
proof of the Raghunathan conjectures" that has provided number-theoretic
information about quadratic forms. Ratner also received
the 1993 Ostrowski Prize in recognition of this work. This prize is
awarded biennially "to one or more mathematicians who during the
preceding five years have accomplished the highest scientific achievement
in pure mathematics or in the theoretical foundations of numerical
analysis."
The description of the 2005 book *Ratner's Theorems on Unipotent Flows* by Dave Witte Morris says that "The theorems of Berkeley mathematician Marina Ratner have guided key advances in the understanding of dynamical systems."

- Chang, Kenneth. "Marina Ratner, Émigré Mathematician Who Found Midlife Acclaim, Dies at 78," New York Times, July 25, 2017
- Wilkinson, Amie. "With Snowflakes and Unicorns, Marina Ratner and Maryam Mirzakhani Explored a Universe in Motion," New York Times, August 7, 2017.
- "Ratner Receives NAS Carty Award," Notices of the American Mathematical Society, 41(5), May/June 1994, 473-474.
- Angwin, Julia. "For the love of her subject-Marina Ratner's energetic path in mathematics," Quantum, July/August 1994, 44.
- "Laczkovich and Ratner Receive Ostrowski Prize," Notices of the American Mathematical Society, 41(6), July/August 1994, 636-637.
- MathSciNet [subscription required]
- Author Profile at zbMath
- Mathematics Genealogy Project