Published online by Cambridge University Press: 21 December 2009
In this paper the absolute value or distance from the origin analogue of the classical Khintchine-Groshev theorem [5] is established for a single linear form with a “slowly decreasing” error function. To explain this in more detail, some notation is introduced. Throughout this paper, m, n are positive integers; i.e., m, n ∈ ℕ; x = (x1,…, xn) will denote a point or vector in ℝn, q = (q1,…, qn) will denote a non-zero vector in ℤn and
|x| := max{|x1|,…,|xn|} = ‖X‖∞
will denote the height of the vector x. Let Ψ : ℕ → (0, ∞) be a (non-zero) function which converges to 0 at ∞. The notion of a slowly decreasing functionΨ is defined in [3] as a function for which, given c ∈ (0, 1), there exists a K = K(c) > 1 such that Ψ(ck) ≤ KΨ(k). Of course, since Ψ is decreasing, Ψ(k) ≤ Ψ(ck). For any set X, |X| will denote the Lebesgue measure of X (there should be no confusion with the height of a vector).