On a sum of Dirichlet characters of a polynomial over reduced system of residues / V. N. Chubarikov. // Vestnik Moskovskogo Universiteta. Seriya 1. Matematika. Mekhanika. 2009. № 3. P.  [Moscow Univ. Math. Bulletin. Vol. 72, N 2, 2017. P. 129-131].

A root estimate is obtained for a sum of Dirichlet characters of the polynomial ax^n+b over a reduced residue system.

Key words: Dirichlet character, Postnikov's formula for a Dirichlet character, Hua Loo-keng's method for estimation of complete rational trigonometric sums.