In this paper, we discuss the relation between the partial sums of Jacobi serier on an elliptic region and the corresponding partial sums of Fourier series. From this we derive a precise approximation formula by the p...In this paper, we discuss the relation between the partial sums of Jacobi serier on an elliptic region and the corresponding partial sums of Fourier series. From this we derive a precise approximation formula by the partial sums of Jacobi series on an elliptic region.展开更多
We prove that for any p perfect set of positive measure and for it＇s any density point x0 one can construct a measurable function f（x）, bounded on [0,1）, such that each measurable and bounded function, which coinc...We prove that for any p perfect set of positive measure and for it＇s any density point x0 one can construct a measurable function f（x）, bounded on [0,1）, such that each measurable and bounded function, which coincides with f（x） on the set p has diverging Fourier-Walsh series on the point xo.展开更多
We give a systematic account of results which assure positivity and boundedness of partial sums of cosine or sine series. New proofs of recent results are sketched.
In this paper,we point out that the Fourier series of a classical function∑^∞k=1 sin kx/k has the Gibbs phenomenon in the neighborhood of zero.Furthermore,we estimate the upper bound of its partial sum and get：sup ...In this paper,we point out that the Fourier series of a classical function∑^∞k=1 sin kx/k has the Gibbs phenomenon in the neighborhood of zero.Furthermore,we estimate the upper bound of its partial sum and get：sup n≥1｜｜∑^n k=1sin kx/k｜｜=∫^x 0sin x/x dx=1.85194, which is better than that in[1].展开更多
This paper deals with the order of magnitude of the partial sums of the spherical harmonic series and its convergence rate in Bessel potential spaces. The partial results obtained in the paper are the analogue of tho...This paper deals with the order of magnitude of the partial sums of the spherical harmonic series and its convergence rate in Bessel potential spaces. The partial results obtained in the paper are the analogue of those on the circle.展开更多
文摘In this paper, we discuss the relation between the partial sums of Jacobi serier on an elliptic region and the corresponding partial sums of Fourier series. From this we derive a precise approximation formula by the partial sums of Jacobi series on an elliptic region.
文摘We prove that for any p perfect set of positive measure and for it＇s any density point x0 one can construct a measurable function f（x）, bounded on [0,1）, such that each measurable and bounded function, which coincides with f（x） on the set p has diverging Fourier-Walsh series on the point xo.
文摘We give a systematic account of results which assure positivity and boundedness of partial sums of cosine or sine series. New proofs of recent results are sketched.
基金Foundation item： the Natural Science Foundation of Zhejiang Province （No. 102058）.
文摘In this paper,we point out that the Fourier series of a classical function∑^∞k=1 sin kx/k has the Gibbs phenomenon in the neighborhood of zero.Furthermore,we estimate the upper bound of its partial sum and get：sup n≥1｜｜∑^n k=1sin kx/k｜｜=∫^x 0sin x/x dx=1.85194, which is better than that in[1].
文摘This paper deals with the order of magnitude of the partial sums of the spherical harmonic series and its convergence rate in Bessel potential spaces. The partial results obtained in the paper are the analogue of those on the circle.
