George Mostow

Born to a Jewish family in Boston, Mostow spent most of his career at Yale, where he served as president of the American Mathematical Society. He is best known for the Mostow rigidity theorem, which proves that the geometry of a closed hyperbolic manifold of dimension three or more is completely determined by its fundamental group — its topology fixes its shape exactly. This surprising and powerful result became a foundation of modern geometry, topology and the study of discrete groups.