Yakov G. Sinai

We are honoured to be able to publish this issue of MMJ, dedicated to Yakov Grigorievich Sinai on the occasion of his 70th birthday.

Yakov Grigorievich Sinai is one of the greatest mathematician of our days. The list of international prizes awarded to him as a sign of recognition of his scientific contributions is extremely long, the list of his fundamental results being even longer. His permanent interest in mathematics and his exceptional scientific enthusiasm inspires several generations of scientists all over the world. His mere presence at a seminar or at a conference makes scientific life brighter and more exiting.

For many years he was one of the organizers of two unique “Moscow style” seminars: on Ergodic Theory and Dynamical Systems and on Statistical Mechanics. To large extent these seminars shaped both subjects and determined research directions of many and many Sinai's students—formal and informal—all over the world. A wonderful atmosphere of creativity and joy of discovery will be remembered by all the participants. For a long time the seminars gave unique opportunity for western scientists to present their results to eastern colleagues, to discuss scientific perspectives and to learn news from the East. And for many of them the inspiring interactive character of these seminars was among most memorable experiences of their scientific life.

Sinai's scientific breadth is another characteristic feature of his style. He made, and continues to make, fundamental contributions to ergodic theory, dynamical systems, statistical mechanics, mathematical physics, probability theory, hydrodynamics. The incredable diversity of Sinai's scientific interests is reflected in particular in the list of his former students, who are themselves well-known scientists, working in diverse areas. It includes the names of M. Blank, P. Bleher, L. Bunimovich, D. Dolgopyat, B. Gurevich, M. Jacobson, S. Jitomirskaya, A. Katok, K. Khanin, Yu. Kifer, A. Kramli, G. Margulis, V. Oseledec, M. Ratner, A. Soshnikov, A. Stepin, Yu. Suhov, and many others.

We wish Yakov Grigorievich many prolific years of scinetific activity, filled with joy of discoveries, admiration of arts and nature, and delights of friendship.

Yu. Ilyashenko, K. Khanin, S. Shlosman, M. Tsfasman