On the divisor problem with congruence conditions

Lirui Jia, Wenguang Zhai, Tianxin Cai

Let $d(n;r_1,q_1,r_2,q_2)$ be the number of factorization $n=n_1{n}_2$ satisfying $n_i\equiv r_i(\mathrm{mod}{q}_i)$ ($i=1,2$) and $\Delta (x;r_1,q_1,r_2,q_2)$ be the error term of the summ…