Dedicated to the memory of Chih-Han Sah, this volume continues a long tradition of one of the most influential mathematical seminars of this century. A number of topics are covered, including combinatorial geometry, connections between logic and geometry, Lie groups, algebras and their representations. An additional area of importance is noncommutative algebra and geometry, and its relations to modern physics. Distinguished mathematicians contributing to this work: T.V. Alekseevskaya V. Kac A.V. Borovik A. Kazarnovsky-Krol C.-H. Sah* M. Kontsevich G. Cherlin A. Radul J.L. Dupont A.L. Rosenberg I.M. Gelfand N. White The Gelfand Mathematical Seminar volumes stimulate the birth of significant ideas in contemporary mathematics and remain invaluable reference material. * indicates deceased contributor (Production: please ensure that appropriate symbol be incorporated onto the final back cover design)