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Asymptotics of polynomial interpolation and the Bernstein constants. (English) Zbl 1468.41005

The author studies new asymptotic bounds for the quantities of the classical Lagrange interpolation error for \(|x|a\), \(a > 0\) when a tends to infinity. Moreover, he gives some explicit constructions for near best approximation polynomials to \(|x|a\), \(a > 0\) in the \(L_\infty\) norm which are based on the Chebyshev interpolation process. Some numerical examples are given.

MSC:

41A05 Interpolation in approximation theory
41A10 Approximation by polynomials
65D05 Numerical interpolation

Software:

DLMF; Chebfun

References:

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[12] Revers, M., On the asymptotics of polynomial interpolation to \(\left|x\right|^{\alpha }\) at the Chebyshev nodes, J. Approx. Theory, 165, 70-82 (2013) · Zbl 1264.41005 · doi:10.1016/j.jat.2012.09.005
[13] Revers, M.: Extremal polynomials and entire functions of exponential type. Results Math. 73, Article No. 109 (2018) · Zbl 1401.41003
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[15] Varga, R.S., Carpenter, A.J.: Some Numerical Results on Best Uniform Polynomial Approximation of \(x^{\alpha }\) on \(\left[0,1\right] \), Lecture Notes Mathematics, vol. 1550, Berlin, Springer, pp. 192-222 (1993) · Zbl 0784.65009
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