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JOURNALS // Izvestiya of Saratov University. Mathematics. Mechanics. Informatics // Archive

Izv. Saratov Univ. Math. Mech. Inform., 2014 Volume 14, Issue 1, Pages 38–47 (Mi isu484)

This article is cited in 3 papers

Mathematics

Asymptotic properties and weighted estimation of polynomials, orthogonal on the nonuniform grids with Jacobi weight

M. S. Sultanakhmedov

Department of Mathematics and Computer Science, Daghestan Scientific Center, 45, M. Gadzhieva str., 367000, Makhachkala, Daghestan, Russia

Abstract: Let $-1=\eta_0<\eta_1<\eta_2<\dots<\eta_{N-1}<\eta_N=1$, $\lambda_N=\max_{0\leq j\leq N-1}(\eta_{j+1}-\eta_j)$. Current work is devoted to investigation of properties of polynomials, orthogonal with Jacobi weight $\kappa^{\alpha,\beta}(t)=(1-t)^\alpha (1+t)^\beta$ on nonuniform grid $\Omega_N=\{t_j\}_{j=0}^{N-1}$, where $\eta_j\leq t_j\leq\eta_{j+1}$. In case of integer $\alpha,\beta\geq0$ for such discrete orthonormal polynomials $\hat P_{n,N}^{\alpha,\beta}(t)$ ($n=0,\ldots,N-1$) asymptotic formula $\hat P_{n,N}^{\alpha,\beta}(t)=\hat P_n^{\alpha,\beta}(t)+\upsilon_{n,N}^{\alpha,\beta}(t)$ with $n=O(\lambda_N^{-1/3})$ ($\lambda_N\to0$) was obtained, where $\hat P_n^{\alpha,\beta}(t)$ – classical Jacobi polynomial, $\upsilon_{n,N}^{\alpha,\beta}(t)$ – remainder term. As corollary of asymptotic formula it was deduced weighted estimation of $\hat P_{n,N}^{\alpha,\beta}(t)$ polynomials on segment $[-1,1]$.

Key words: orthogonal polynomials, nonuniform grid, asymptotic formula, weighted estimation.

UDC: 517.518.82

DOI: 10.18500/1816-9791-2014-14-1-38-47



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