scholarly journals Tridiagonal Operators and Zeros of Polynomials in Two Variables

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Chrysi G. Kokologiannaki ◽  
Eugenia N. Petropoulou ◽  
Dimitris Rizos

The aim of this paper is to connect the zeros of polynomials in two variables with the eigenvalues of a self-adjoint operator. This is done by use of a functional-analytic method. The polynomials in two variables are assumed to satisfy a five-term recurrence relation, similar to the three-term recurrence relation that the classical orthogonal polynomials satisfy.

2015 ◽  
Vol 58 (4) ◽  
pp. 877-890
Author(s):  
Mohamed Zaatra

AbstractWe show that if v is a regular semi-classical form (linear functional), then the symmetric form u defined by the relation x2σu = -λv, where (σƒ )(x) = f (x2) and the odd moments of u are 0, is also regular and semi-classical form for every complex λ except for a discrete set of numbers depending on v. We give explicitly the three-term recurrence relation and the structure relation coefficients of the orthogonal polynomials sequence associated with u and the class of the form u knowing that of v. We conclude with an illustrative example.


In a recent paper the first two authors studied a class of series inequalities associated with a three-term recurrence relation which includes a well-known inequality of Copson’s. It was shown that the validity of the inequality and the value of the best constant are determined in term s of the so-called Hellinger-Nevanlinnam -function. The theory is the discrete analogue of that established by Everitt for a class of integro-differential inequalities. In this paper the properties of the m -function are investigated and connections with the theory of orthogonal polynomials and the H am burger moment problem are explored. The results are applied to give examples of the series inequalities associated with the classical orthogonal polynomials.


Author(s):  
Gradimir Milovanovic ◽  
Aleksandar Cvetkovic

In this paper we are concerned with polynomials orthogonal with respect to the generalized Hermite weight function w(x) = |x ? z|? exp(?x2) on R, where z?R and ? > ? 1. We give a numerically stable method for finding recursion coefficients in the three term recurrence relation for such orthogonal polynomials, using some nonlinear recurrence relations, asymptotic expansions, as well as the discretized Stieltjes-Gautschi procedure.


2010 ◽  
Vol 17 (3) ◽  
pp. 581-596
Author(s):  
Mabrouk Sghaier

Abstract We study properties of the form (linear functional) u = λ(x – a)–1 ν + δb , where ν is a regular form. We give a necessary and sufficient condition for the regularity of the form u. The coefficients of a three-term recurrence relation, satisfied by the corresponding sequence of orthogonal polynomials, are given explicitly. The semi-classical character of the founded families is studied. We conclude by giving some examples.


Author(s):  
Joaquin Bustoz ◽  
Mourad E. H. Ismail

A method is outlined to express a Turán determinant of solutions of a three term recurrence relation as a weighted sum of squares. This method is shown to imply the positivity of Turán determinants of symmetric Pollaczek polynomials, Lommel polynomials andq-Bessel functions.


1994 ◽  
Vol 124 (5) ◽  
pp. 1003-1011 ◽  
Author(s):  
Pascal Maroni ◽  
Jeannette Van Iseghem

An orthogonal family of polynomials is given, and a link is made between the special form of the coefficients of their recurrence relation and a first-order linear homogenous partial differential equation satisfied by the associated generating function. A study is also made of the semiclassical character of such families.


Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1972
Author(s):  
Albertus C. den Brinker

Deployment of the recurrence relation or difference equation to generate discrete classical orthogonal polynomials is vulnerable to error propagation. This issue is addressed for the case of Krawtchouk functions, i.e., the orthonormal basis derived from the Krawtchouk polynomials. An algorithm is proposed for stable determination of these functions. This is achieved by defining proper initial points for the start of the recursions, balancing the order of the direction in which recursions are executed and adaptively restricting the range over which equations are applied. The adaptation is controlled by a user-specified deviation from unit norm. The theoretical background is given, the algorithmic concept is explained and the effect of controlled accuracy is demonstrated by examples.


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