On the generalized exponential sums and their fourth power mean
The paper is devoted to the calculation of the sums \[ \frac{1}{p-1} \sum_{\chi \bmod p}\left|\sum_{a=1}^{p-1} \chi(a) e\left(\frac{a^2+a}{p}\right)\right|^4 \] and \[ \frac{1}{p-1} \sum_{\chi \bmod p}\left|\sum_{a=1}^{p-1} \chi(a) e\left(\frac{a^3}{p}\right)\right|^4, \] where \(p\) is an odd prime, \(e(y)= e^{2\pi iy}\) and \(\chi\) is a Dirichlet character modulo \(p\).
scientific article; zbMATH DE number 7903507