EN
Let α be an irrational and φ: ℕ → ℝ⁺ be a function decreasing to zero. Let $ω(α):= sup {θ ≥ 1: lim inf_{n→ ∞}n^{θ} ||nα}|=0}$. For any α with a given ω(α), we give some sharp estimates for the Hausdorff dimension of the set
$E_{φ}(α)$ := {y ∈ ℝ: ||nα -y|| < φ(n) for infinitely many n},
where ||·|| denotes the distance to the nearest integer.