First and second kind paraorthogonal polynomials and their zeros

نویسنده

  • Manwah Lilian Wong
چکیده

Given a probability measure μ with infinite support on the unit circle ∂D = {z : |z| = 1}, we consider a sequence of paraorthogonal polynomials hn(z, λ) vanishing at z = λ where λ ∈ ∂D is fixed. We prove that for any fixed z0 6∈ supp(dμ) distinct from λ, we can find an explicit ρ > 0 independent of n such that either hn or hn+1 (or both) has no zero inside the disk B(z0, ρ), with the possible exception of λ. Then we introduce paraorthogonal polynomials of the second kind, denoted sn(z, λ). We prove three results concerning sn and hn. First, we prove that zeros of sn and hn interlace. Second, for z0 an isolated point in supp(dμ), we find an explicit radius ρ̃ such that either sn or sn+1 (or both) have no zeros inside B(z0, ρ̃). Finally we prove that for such z0 we can find an explicit radius such that either hn or hn+1 (or both) has at most one zero inside the ball B(z0, ρ̃).

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

An Electrostatic Interpretation of the Zeros of Paraorthogonal Polynomials on the Unit Circle

We show that if μ is a probability measure with infinite support on the unit circle having no singular component and a differentiable weight, then the corresponding paraorthogonal polynomial Φn(z;β) solves an explicit second order linear differential equation. We also show that if τ 6= β, then the pair (Φn(z;β),Φn(z; τ)) solves an explicit first order linear system of differential equations. On...

متن کامل

Rank one perturbations and the zeros of paraorthogonal polynomials on the unit circle

We prove several results about zeros of paraorthogonal polynomials using the theory of rank one perturbations of unitary operators. In particular, we obtain new details on the interlacing of zeros for successive POPUC. © 2006 Elsevier Inc. All rights reserved.

متن کامل

The statistical distribution of the zeros of random paraorthogonal polynomials on the unit circle

We consider polynomials on the unit circle defined by the recurrence relation Φk+1(z) = zΦk(z)− αkΦk(z) k ≥ 0, Φ0 = 1 For each n we take α0, α1, . . . , αn−2 i.i.d. random variables distributed uniformly in a disk of radius r < 1 and αn−1 another random variable independent of the previous ones and distributed uniformly on the unit circle. The previous recurrence relation gives a sequence of ra...

متن کامل

Application of Chebyshev Polynomials for Solving Abel's Integral Equations of the First and Second Kind

In this paper, a numerical implementation of an expansion method is developed for solving Abel's integral equations of the first and second kind. The solution of such equations may demonstrate a singular behaviour in the neighbourhood of the initial point of the interval ofintegration. The suggested method is based on the use of Taylor series expansion to overcome the singularity which le...

متن کامل

Szegő Quadrature and Frequency Analysis∗

Abstract. A series of papers have treated the frequency analysis problem by studying the zeros of orthogonal polynomials on the unit circle with respect to measures determined by observations of the signal. In the recent paper [3], a different approach was used, where properties of Szegő quadrature formulas associated with the zeros of paraorthogonal polynomials with respect to the same measure...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of Approximation Theory

دوره 146  شماره 

صفحات  -

تاریخ انتشار 2007