【摘要】 讨论了雅可比展开的黎斯算子的若干逼近性质．建立了黎斯算子与Ｋ泛函之间的强渐近等价关系．引进黎斯算子的迭代算子，从而用以实现Ｋ泛函收敛阶的刻划，并且用于代数多项式加权最佳逼近的逼近阶描述．更多还原

【Abstract】 The paper deals with the convegence of Riesz operators for Jacobi expansions. The equivalence between Riesz operators and K functionals is established. It is proved that the iterations of Riesz operators can serve as a realization of the K functionals. The results obtained in the paper are also applied to describe the order of best approximation by algebraic polynomials with weights.更多还原