English

Approximating reals by sums of two rationals

Number Theory 2007-05-23 v2

Abstract

We generalize Dirichlet's diophantine approximation theorem to approximating any real number α\alpha by a sum of two rational numbers a1q1+a2q2\frac{a_1}{q_1} + \frac{a_2}{q_2} with denominators 1q1,q2N1 \leq q_1, q_2 \leq N. This turns out to be related to the congruence equation problem xyc(modq)x y \equiv c \pmod q with 1x,yq1/2+ϵ1 \leq x, y \leq q^{1/2 + \epsilon}.

Keywords

Cite

@article{arxiv.math/0609322,
  title  = {Approximating reals by sums of two rationals},
  author = {Tsz Ho Chan},
  journal= {arXiv preprint arXiv:math/0609322},
  year   = {2007}
}

Comments

13 pages, improved results and some changes in the proofs

R2 v1 2026-07-22T17:42:18.405Z