%0 Journal Article %T Khinchin theorem for integral points on quadratic varieties %A Alexander Gorodnik %A Nimish A. Shah %J Mathematics %D 2008 %I arXiv %X We prove an analogue the Khinchin theorem for the Diophantine approximation by integer vectors lying on a quadratic variety. The proof is based on the study of a dynamical system on a homogeneous space of the orthogonal group. We show that in this system, generic trajectories visit a family of shrinking subsets infinitely often. %U http://arxiv.org/abs/0804.3530v1