Jackson’s theorem in Q_p spaces

• 作 者: YingWei Chen (1) cyingwei@mail
• 出 处: 中国科学：数学英文版
• 发表日期: 2010年2期
• 关键词: Q P space BMOA POLYNOMIAL approximation Q p spaceBMOApolynomial approximation
• 基金项目: Supported by the Unidade de Investigao “Matemtica e Aplicaoes” of University of Aveiro, National Natural Science Foundation of China (Grant No. 10771201),New Century Excellent Talentsin University

A Jackson type inequality in Q p spaces is established, i.e., for any f (z) = Σ∞ j=0 ajzj ∈ Qp , 0≤p 【 ∞, a 】 1, and k-1 ∈ N,where ω(1/k, f, Q p ) is the modulus of continuity in Q p spaces and C(a) is an absolute constant depending only on the parameter