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Uniform Lebesgue constants of local spline approximation
V. T. Shevaldin Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg
Abstract:
Let a function φ∈C1[−h,h] be such that φ(0)=φ′(0)=0, φ(−x)=φ(x) for x∈[0;h]), and φ(x) is nondecreasing on [0;h]. For any function f: R→R, we consider local splines of the form S(x)=Sφ(f,x)=∑j∈ZyjBφ(x+3h2−jh)(x∈R), where yj=f(jh), m(h)>0, and Bφ(x)=m(h){φ(x),x∈[0;h],2φ(h)−φ(x−h)−φ(2h−x),x∈[h;2h],φ(3h−x),x∈[2h;3h],0,x∉[0;3h]. These splines become parabolic, exponential, trigonometric, etc., under the corresponding choice of the function φ. We study the uniform Lebesgue constants Lφ=‖S‖CC (the norms of linear operators from C to C) of these splines as functions depending on φ and h. In some cases, the constants are calculated exactly on the axis R and on a closed interval of the real line (under a certain choice of boundary conditions from the spline Sφ(f,x)).
Keywords:
Lebesgue constants, local splines, three-point system.
Received: 02.06.2017
Citation:
V. T. Shevaldin, “Uniform Lebesgue constants of local spline approximation”, Trudy Inst. Mat. i Mekh. UrO RAN, 23, no. 3, 2017, 292–299; Proc. Steklov Inst. Math. (Suppl.), 303, suppl. 1 (2018), 196–202
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https://www.mathnet.ru/eng/timm1459 https://www.mathnet.ru/eng/timm/v23/i3/p292
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Abstract page: | 224 | Full-text PDF : | 51 | References: | 44 | First page: | 12 |
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