非線形問題と複素幾何学
《非線形問題と複素幾何学》 · 第 272 页 · Section 11.11「General Exponential Sums」
Still more generally, one can mix additive and multiplicative characters, and define sums such as $S_\chi(f,g)=\sum_{x\in\mathbb F}^{*}\chi(f(x))\psi(g(x))$, an example of which is the Salié sum $T(a,b;p)=\sum_{x\bmod p}^{*}(\frac{x}{p})e((ax+b\bar x)/p)$.