Rational approximation and arithmetic progressions

A reasonably complete theory of the approximation of an irrational by rational fractions whose numerators and denominators lie in prescribed arithmetic progressions is developed in this paper. Results are both, on the one hand, from a metrical and a non-metrical point of view and, on the other hand, from an asymptotic and also a uniform point of view. The principal novelty is a Khintchine type theorem for uniform approximation in this context. Some applications of this theory are also discussed

Khinchin theorem for integral points on quadratic varieties

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.Comment: 19 page

A note on Linnik\u2019s approach to the Dirichlet L-functions

Let $chi$ (mod $q$), q>1, be a primitive Dirichlet character. We first present a detailed account of Linnik's deduction of the functional equation of $L(s,chi)$ from the functional equation of $zeta(s)$. Then we show that the opposite deduction can be obtained by a suitable modification of the method, involving finer arithmetic arguments

THE METRIC THEORY OF MIXED TYPE LINEAR FORMS

In this paper the metric theory of Diophantine approximation of linear forms that are of mixed type is investigated. Khintchine-Groshev theorems are established together with the Hausdorff measure generalizations. The latter includes the original dimension results obtained in [H. Dickinson, The Hausdorff dimension of sets arising in metric Diophantine approximation, Acta Arith. 68(2) (1994) 133-140] as special case