On the metric theory of approximations by reduced fractions: a quantitative Koukoulopoulos-Maynard theorem

Christoph Aistleitner, Bence Borda, Manuel Hauke

Let $\psi :\mathbb{N}\to [0,1/2]$ be given. The Duffin-Schaeffer conjecture, recently resolved by Koukoulopoulos and Maynard, asserts that for almost all reals $\alpha$ there are infinite…