|
Trudy Instituta Matematiki i Mekhaniki UrO RAN, 2010, Volume 16, Number 4, Pages 65–73
(Mi timm641)
|
|
|
|
Some properties of Jacobi polynomials orthogonal on a circle
V. M. Badkov Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences
Abstract:
Let {ψ(α,β)n(z)}∞n=0 be a system of Jacobi polynomials that is orthonormal on the circle |z|=1 with respect to the weight (1−cosτ)α+1/2(1+cosτ)β+1/2 (α,β>−1), and let ψ(α,β)∗n(z):=zn¯ψ(α,β)n(1/¯z). We establish relations between the polynomial ψ(α,−1/2)n(z) and the n-th (C,α−1/2)-mean of the Maclaurin series for the function (1−z)−α−3/2 and also between the polynomial ψ(α,−1/2)∗n(z) and the n-th (C,α+1/2)-mean of the Maclaurin series for the function (1−z)−α−1/2. We use these relations to derive an asymptotic formula for ψ(α,−1/2)n(z); the formula is uniform inside the disk |z|<1. It follows that ψ(α,−1/2)n(z)≠0 in the disk |z|⩽ρ for fixed ρ∈(0,1) and α>−1 if n is sufficiently large.
Keywords:
Jacobi polynomials, Cesáaro means, asymptotic formula, zeros.
Received: 11.02.2010
Citation:
V. M. Badkov, “Some properties of Jacobi polynomials orthogonal on a circle”, Trudy Inst. Mat. i Mekh. UrO RAN, 16, no. 4, 2010, 65–73; Proc. Steklov Inst. Math. (Suppl.), 273, suppl. 1 (2011), S49–S58
Linking options:
https://www.mathnet.ru/eng/timm641 https://www.mathnet.ru/eng/timm/v16/i4/p65
|
Statistics & downloads: |
Abstract page: | 316 | Full-text PDF : | 115 | References: | 61 | First page: | 1 |
|