Kenneth Ribet

Kenneth Alan Ribet (; born June 28, 1948) is an American mathematician working in algebraic number theory and algebraic geometry. He is known for the Herbrand–Ribet theorem and Ribet's theorem, which were key ingredients in the proof of Fermat's Last Theorem, as well as for his service as President of the American Mathematical Society from 2017 to 2019. He is currently a professor of mathematics at the University of California, Berkeley.

Early life and education Kenneth Ribet was born in Brooklyn, New York to parents David Ribet and Pearl Ribet, both Jewish, on June 28, 1948. As a student at Far Rockaway High School, Ribet was on a competitive mathematics team, but his first field of study was chemistry.

Ribet earned his bachelor's degree and master's degree from Brown University in 1969. An earlier theorem of Ribet's, the Herbrand–Ribet theorem, is the converse to Herbrand's theorem on the divisibility properties of Bernoulli numbers and is also related to Fermat's Last Theorem.

Awards and honors Ribet received the Fermat Prize in 1989 jointly with Abbas Bahri. In 2017, Ribet received the Brouwer Medal. For 2025 Ribet was awarded the AMS Leroy P. Steele Prize for Seminal Contribution to Research.

In 1988, Ribet was inducted as a vigneron d'honneur by the Jurade de Saint-Émilion.

Personal life Ribet is married to statistician Lisa Goldberg.