THE 1996/7 WOLF FOUNDATION PRIZE IN MATHEMATICS

The Prize Committee for Mathematics has unanimously decided that the Wolf Prize for 1996/7 be jointly awarded to:

**YAKOV G. SINAI Princeton University Princeton, New Jersey, USA and Landau Institute of Theoretical Physics Moscow, Russia.**

for his fundamental contributions to mathematically rigorous methods in statistical mechanics and the ergodic theory of dynamical systems and their applications in physics.

JOSEPH B. KELLER

Stanford University

Stanford, California, USA

for his profound and innovative contributions, in particular to electromagnetic, optical, acoustic wave propagation and to fluid, solid, quantum and statistical mechanics.

Professor Joseph B. Keller is a preeminent applied mathematician in the classical tradition. He has brought a deep understanding of physics and a superb skill at asymptotics to an astonishing range of problems; these include reflection, scattering and diffraction of waves, whether acoustic, electro-magnetic, elastic or fluid. His outstanding contributions cover problems in mechanics, quantum mechanics, thermo-dynamics, statistical mechanics, and include the so- called Keller-Maslov index, the Keller-Rubinov formula for forward scattering and pioneering work on random media. He is really the model of what a mathematician interested in a wide variety of physical phenomena can and should be.

Professor Yakov G. Sinai brings to bear on the problems of mathematical physics the powerful tools of dynamical systems and probability theory, often developing new tools for this purpose. He is generally recognized as the world leader in the mathematics of statistical physics. Working in the tradition of the Kolmogorov school, he first formulated the rigorous definition of the invariant entropy for an arbitrary measure-preserving map. His subsequent work covers areas from the ergodicity of the motion of billiards to spectral properties of quasi-periodic Schrödinger operators. Statistical mechanics is one of the most active and rewarding areas of modern mathematics and Yakov Sinai is its recognized leader today.