Abstract
In this paper, we establish lower bounds for n-term approximations in the metric of L 2(I2) of characteristic functions of plane convex subsets of the square I 2 with respect to arbitrary orthogonal systems. It is shown that, as n→∞, these bounds cannot decrease more rapidly than \(1/n\).
Similar content being viewed by others
REFERENCES
R. A. De Vore, “Nonlinear approximation,” Acta Numerica, 7 (1998), 51-150.
V. N. Temlyakov, Nonlinear Methods of Approximations, IMI Preprint 2001:09, University of South Carolina, 2001.
B. S. Kashin, “On lower estimates for n-term approximation in Hilbert space,” in: Approximation Theory. Volume Dedicated to B. Sendov, Darba, Sofia, 2002, pp. 241-257.
B. S. Kashin, “On the approximation properties of complete orthonormal systems,” Trudy Mat. Inst. Steklov [Proc. Steklov Inst. Math.], 172 (1985), 187-191.
A. Cohen, R. De Vore, P. Petrushev, and H. Xu, “Nonlinear approximation and the space BV (ℝ2),” Amer. J. Math., 121 (1999), 587-628.
D. L. Donoho, “Sparse components of images and optimal atomic decompositions,” Constr. Approx., 17 (2001), no. 3, 353-382.
I. Daubechies, Ten Lectures on Wavelets [Russian translation], RKhD, Moscow-Izhevsk, 2001.
B. S. Kashin and T. Yu. Kulikova, “A note on the approximation properties of frames of general form,” Mat. Zametki [Math. Notes], 72 (2002), no. 2, 312-315.
B. S. Kashin and A. A. Saakyan, Orthogonal Series [in Russian], 2nd edition, AFTs, Moscow, 1999.
R. P. Agnew, “On double orthogonal series,” Proc. London Math. Soc. Ser. 2, 33 (1932), no. 6, 420-434.
F. Moricz, “Multiparameter strong laws of large numbers. I,” Acta Sci. Math., 40 (1978), 143-156.
B. S. Kashin, “On the coefficients of the expansion of a class of functions in complete systems,” Sibirsk. Mat. Zh. [Siberian Math. J.], 18 (1977), no. 1, 122-131.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kashin, B.S. Lower Bounds for n-Term Approximations of Plane Convex Sets and Related Topics. Mathematical Notes 72, 473–478 (2002). https://doi.org/10.1023/A:1020528210992
Issue Date:
DOI: https://doi.org/10.1023/A:1020528210992