Direct and strong converse inequalities for approximation with Fejér means

[摘要] We present upper and lower estimates of the error of approximation of periodic functions by Fejér means in the Lebesgue spaces L2πp{L}_{2{\pi }}^{p}. The estimates are given in terms of a K -functional for 1≤p≤∞1\le p\le \infty and in terms of the first modulus of continuity in the case 1

[学科分类] 外科医学

[关键词] Fejér operators;rate of convergence;direct and converse results