<正>Let {vij}, i, j = 1, 2,…, be i.i.d. random variables with Ev11= 0, Ev112=1 and ai = (ai1,…,aiM) be random vectors with {aij} being i.i.d. random variables
<正>To obtain a better Vinogradov's bound, assistant function with two or three zeros and all Dirichlet's characters has been evaluated. Assistant funct