Type: Article
Publication Date: 2009-06-25
Citations: 50
DOI: https://doi.org/10.1090/s0002-9947-09-04788-6
Let $p_n$ denote the $n^{\textrm {th}}$ prime. Goldston, Pintz, and Yıldırım recently proved that \begin{equation*} \liminf _{n\to \infty } \frac {(p_{n+1}-p_n)}{\log p_n} =0. \end{equation*} We give an alternative proof of this result. We also prove some corresponding results for numbers with two prime factors. Let $q_n$ denote the $n^{\textrm {th}}$ number that is a product of exactly two distinct primes. We prove that \begin{equation*} \liminf _{n\to \infty } (q_{n+1}-q_n) \le 26. \end{equation*} If an appropriate generalization of the Elliott-Halberstam Conjecture is true, then the above bound can be improved to $6$.