Bilinear forms with Kloosterman fractions and applications
We establish improved bounds for bilinear forms with Kloosterman fractions of the form ${\sum\sum}_{m,n} α_m β_n e(a\overline{m}/(bn))$ with $M<m\le 2M$, $N < n \le 2N$ and $(m,n)=1$. Our approach works directly with arbitrary coefficient sequences $(α_m), (β_n) \in \mathbb{C}$, avoiding the temporary restriction to squarefree support...