关键词: Kloosterman和, 指数和, 分圆域, 代数数

Abstract: The generating fields of the twisted Kloosterman sums Kl (q, a, χ) and the partial Gauss sums g(q, a, χ) are studied.We require that the characteristic p is large with respect to the order d of the character χ and the trace of the coefficient a is nonzero.When p≡±1 mod d,we can characterize the generating fields of these character sums.For general p,when a lies in the prime field,we propose a combinatorial condition on (p, d) to ensure one can determine the generating fields.

Key words: Kloosterman sum, exponential sum, cyclotomic field, algebraic number