
doi: 10.1007/bf00113913
The paper is concerned with a weighted \((0; 0,2)\)-interpolation problem. It is shown that for each even natural number \(n\) and arbitrary numbers \((\alpha_{j, n})^n_{j= 1}\), \((\beta_{ j,n })^{n- 1}_{j=1}\), \((\gamma_{ j,n })^{n-1}_{j =1}\), there exists a uniquely determined polynomial \(P_n\) of degree at most \(3n-2\) such that \[ P_n (x_{j,n})= \alpha_{j,n}, \quad j=1, \dots, n, \qquad P_n (y_{j, n})= \beta_{j, n}, \quad j=1, \dots, n-1, \tag \(*\) \] and \[ (e^{-x^2/ 2} P_n (x) )'_{x= y_{j,n}}= \gamma_{j, n}, \quad j=1, \dots, n-1, \qquad P'_n (0)= \sum^n_{j=1} {{\alpha_{j,n} l_{j,n} (0)^2 H_n' (0)} \over {H_n' (x_{j,n})}}, \tag \(**\) \] where the numbers \((x_{j, n})^n_{j=1}\) and \((y_{j, n})^{n-1}_{j=1}\) are the zeros of the \(n\)-th Hermite polynomial \(H_n\) and its first derivative \(H_n'\), and the polynomials \((l_{j,n})^n_{j=1}\) are the fundamental polynomials of Lagrange interpolation with respect to \((x_{j, n})^n_{j=1}\). In the paper an explicit expression for the polynomial \(P_n\) is given in terms of fundamental polynomials of the first and second kind. Moreover, for a suitable class of continuously differentiable functions \(f: \mathbb{R}\to \mathbb{R}\) the term \(e^{-\nu x^2} |P_n (f, x)- f(x)|\) is estimated on the whole real line, where \(\nu> 3/2\) and the polynomials \(P_n (f, \cdot)\) are determined by \((*)\) and \((**)\), taking \((\alpha_{j, n})^n_{j=1}= (f (x_{j,n} ))^n_{j=1}\), \((\beta_{ j,n })^{n- 1}_{j =1}= (f(y_{ j,n }))^{n- 1}_{j=1}\) and choosing the numbers \((\gamma_{ j,n })^{n- 1}_{j=1}\) in a suitable way.
Orthogonal polynomials and functions of hypergeometric type (Jacobi, Laguerre, Hermite, Askey scheme, etc.), weighted interpolation, roots of Hermite polynomials, Approximation by polynomials, approximation by polynomials, Interpolation in approximation theory
Orthogonal polynomials and functions of hypergeometric type (Jacobi, Laguerre, Hermite, Askey scheme, etc.), weighted interpolation, roots of Hermite polynomials, Approximation by polynomials, approximation by polynomials, Interpolation in approximation theory
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 2 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
