On the Divergence of Lagrange Interpolation to |x|
β Scribed by L. Brutman; E. Passow
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 227 KB
- Volume
- 81
- Category
- Article
- ISSN
- 0021-9045
No coin nor oath required. For personal study only.
β¦ Synopsis
It is a classical result of Bernstein that the sequence of Lagrange interpolation polynomials to (|x|) at equally spaced nodes in ([-1,1]) diverges everywhere, except at zero and the end-points. In the present paper we show that the case of equally spaced nodes is not an exceptional one in this sense. Namely, we prove that the divergence everywhere in (0<|x|<1) of the Lagrange interpolation to (|x|) takes place for a broad family of nodes, including in particular the Newman nodes, which are known to be very efficient for rational interpolation. (1995 Academic Press, Inc.
π SIMILAR VOLUMES
Given a compact interval 2, it is shown that for E. A. Rakhmanov's weight w on 2 which is bounded from below by the Chebyshev weight v on 2 (1982, Math. USSR Sb. 42, 263) the corresponding orthonormal polynomials are unbounded in every L p v (and L p w ) with p>2 and also that the Lagrange interpola
We estimate the distribution function of a Lagrange interpolation polynomial and deduce mean boundedness in L p , p<1. 1999 Academic Press ## 1. THE RESULT There is a vast literature on mean convergence of Lagrange interpolation, see [4 8] for recent references. In this note, we use distribution
Necessary and sufficient conditions are obtained for a continuous function guaranteeing the uniform convergence on the whole interval [ &1, 1] of its Lagrange interpolant based on the Jacobi nodes. The conditions are in terms of 4-variation, 8-variation, the modulus of variation, and the Banach indi