##### BIO

**Yakov Eliashberg** (St. Petersburg, Russia, 1946), an American national, earned his PhD in 1972 from what was then Leningrad University, under the direction of Vladimir Rikhlin. That same year, he took up an appointment at newly founded Syktyvkar University in the capital of the Komi republic, leading the Mathematics Department there until his departure in 1979. From 1981 to 1987 he worked as a software engineer at the Leningrad Institute of Accounting, cut off from academic life by the Soviet authorities following his application for an emigration visa. In 1988 he was finally able to emigrate to the United States, and since 1989 has taught at Stanford University, where he is currently the Herald L. and Caroline L. Ritch Professor of Mathematics. Eliashberg has held visiting positions at universities in seven countries – from the U.S. to Japan by way of Switzerland and the United Kingdom – and is an Associate Editor of the *Journal of Symplectic Geometry*, as well as serving on the editorial board of *Geometry and Topology*.

##### CONTRIBUTION

Born in Leningrad (now St. Petersburg) in 1946, Eliashberg’s first passion was not numbers and equations, but music. However his teacher at a young people’s mathematics club woke in him a fascination for the subject, which he would go on to choose for his degree course at Leningrad University. Despite being a brilliant student and performing outstandingly with his doctoral thesis, he suffered severe discrimination under the Soviet regime, which even expelled him from the university where he worked, initiating a period of eight years in which he was cut off from mathematical life. In 1987 he was allowed at last to travel to the United States, where he would reignite his brilliant research career.

The awardee helped found symplectic geometry and a related field, symplectic topology, likewise concerned with the objects that describe motion but with a focus on those of their properties that do not change when the objects deform. Eliashberg was also responsible, with Mikhail Gromov, for establishing the homotopy principle, which allows to solve differential equations and differential relations, and has applications in many different areas of mathematics. With Helmut Hofer and Alexander Givental, he shaped the new branch of contact geometry and, within symplectic geometry and topology, pioneered an entire subfield closer to algebraic geometry known as symplectic field theory.