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The Symmetric Meixner-Pollaczek polynomialsAraaya, Tsehaye January 2003 (has links)
<p>The Symmetric Meixner-Pollaczek polynomials are considered. We denote these polynomials in this thesis by <i>p</i><i>n</i><sup>(λ)</sup>(<i>x</i>) instead of the standard notation <i>p</i><i>n</i><sup>(λ)</sup> (<i>x</i>/2, <i>π</i>/2), where λ > 0. The limiting case of these sequences of polynomials <i>p</i><i>n</i><sup>(0)</sup> (<i>x</i>) =lim<sub>λ→0</sub> <i>p</i><i>n</i><sup>(λ)</sup>(<i>x</i>), is obtained, and is shown to be an orthogonal sequence in the strip, <i>S</i> = {<i>z</i> ∈ ℂ : −1≤ℭ (<i>z</i>)≤1}.</p><p>From the point of view of Umbral Calculus, this sequence has a special property that makes it unique in the Symmetric Meixner-Pollaczek class of polynomials: it is of convolution type. A convolution type sequence of polynomials has a unique associated operator called a delta operator. Such an operator is found for <i>p</i><i>n</i><sup>(0)</sup> (<i>x</i>), and its integral representation is developed. A convolution type sequence of polynomials may have associated Sheffer sequences of polynomials. The set of associated Sheffer sequences of the sequence <i>p</i><i>n</i><sup>(0)</sup>(<i>x</i>) is obtained, and is found</p><p>to be ℙ = {{<i>p</i><i>n</i><sup>(λ)</sup> (<i>x</i>)} =0 : λ ∈ R}. The major properties of these sequences of polynomials are studied.</p><p>The polynomials {<i>p</i><i>n</i><sup>(λ)</sup> (<i>x</i>)}<sup>∞</sup><i>n</i><sub>=0</sub>, λ < 0, are not orthogonal polynomials on the real line with respect to any positive real measure for failing to satisfy Favard’s three term recurrence relation condition. For every λ ≤ 0, an associated nonstandard inner product is defined with respect to which <i>p</i><i>n</i><sup>(λ)</sup>(x) is orthogonal. </p><p>Finally, the connection and linearization problems for the Symmetric Meixner-Pollaczek polynomials are solved. In solving the connection problem the convolution property of the polynomials is exploited, which in turn helps to solve the general linearization problem.</p>
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The Symmetric Meixner-Pollaczek polynomialsAraaya, Tsehaye January 2003 (has links)
The Symmetric Meixner-Pollaczek polynomials are considered. We denote these polynomials in this thesis by pn(λ)(x) instead of the standard notation pn(λ) (x/2, π/2), where λ > 0. The limiting case of these sequences of polynomials pn(0) (x) =limλ→0 pn(λ)(x), is obtained, and is shown to be an orthogonal sequence in the strip, S = {z ∈ ℂ : −1≤ℭ (z)≤1}. From the point of view of Umbral Calculus, this sequence has a special property that makes it unique in the Symmetric Meixner-Pollaczek class of polynomials: it is of convolution type. A convolution type sequence of polynomials has a unique associated operator called a delta operator. Such an operator is found for pn(0) (x), and its integral representation is developed. A convolution type sequence of polynomials may have associated Sheffer sequences of polynomials. The set of associated Sheffer sequences of the sequence pn(0)(x) is obtained, and is found to be ℙ = {{pn(λ) (x)} =0 : λ ∈ R}. The major properties of these sequences of polynomials are studied. The polynomials {pn(λ) (x)}∞n=0, λ < 0, are not orthogonal polynomials on the real line with respect to any positive real measure for failing to satisfy Favard’s three term recurrence relation condition. For every λ ≤ 0, an associated nonstandard inner product is defined with respect to which pn(λ)(x) is orthogonal. Finally, the connection and linearization problems for the Symmetric Meixner-Pollaczek polynomials are solved. In solving the connection problem the convolution property of the polynomials is exploited, which in turn helps to solve the general linearization problem.
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Fonctions génératrices des polynômes de Hartley des algèbres de Lie simples de rang 2.Pelletier, Xavier 09 1900 (has links)
Ce mémoire étudie deux familles de fonctions orthogonales, soit les fonctions d'orbite de Weyl et les fonctions d'orbite de Hartley. Chacune de ces familles est associée à une algèbre de Lie simple et cette recherche se limite aux algèbres A₂, C₂ et G₂ de rang 2. Les fonctions d'orbite de Weyl ont été largement étudiées depuis des années en raison de leurs propriétés exceptionnelles. Nouvellement, elles ont été utilisées pour générer des polynômes de Chebyshev généralisés et calculer les fonctions génératrices de ces polynômes pour les algèbres de Lie simples de rang 2. Les fonctions d'orbite de Hartley, quant à elles, ont été récemment introduites par Hrivnák et Juránek et l'étude de ces dernières ne fait que débuter. L'objectif de ce mémoire est de définir des polynômes de Chebyshev généralisés associés aux fonctions de Hartley et de calculer les fonctions génératrices de ceux-ci pour les algèbres A₂, C₂ et G₂. Le premier chapitre introduit les systèmes de racines et le groupe de Weyl, original et affine, ainsi que leurs domaines fondamentaux, afin que le lecteur ait les notations et définitions pour comprendre les chapitres suivants. Le deuxième chapitre présente et étudie les fonctions de Weyl. Il définit également leurs polynômes de Chebyshev généralisés et se termine en présentant les différentes fonctions génératrices de ces polynômes pour les algèbres de Lie simples de rang 2. Finalement, le troisième chapitre contient les résultats originaux; il expose les fonctions de Hartley et certaines de leurs propriétés. Il définit les polynômes de Chebyshev généralisés de celles-ci et énonce également leurs relations d'orthogonalité discrète. Il conclut en calculant les fonctions génératrices de ces polynômes pour les algèbres A₂, C₂ et G₂. / This master's thesis studies two families of orthogonal functions, the Weyl orbit functions and the Hartley orbit functions. Each of these families is associated to a simple Lie algebra and the present work is limited to the algebras A₂, C₂ and G₂ of rank 2. Weyl orbit functions have been widely studied for years because of their exceptional properties. Recently, these properties have been used to generate generalized Chebyshev polynomials and to compute the generating functions of these polynomials for the simple Lie algebras of rank 2. Hartley orbit functions, on the other hand, were recently introduced by Hrivnák and Juránek and the study of the latter has only begun. The objective of this thesis is to define the generalized Chebyshev polynomials of Hartley orbit functions and to compute their generating functions for the algebras A₂, C₂ and G₂. The first chapter introduces root systems and the Weyl group, original and affine, and their fundamental domains, so that the reader has the notations and definitions at hand to read the following chapters. The second chapter introduces and studies Weyl orbit functions. It also defines their generalized Chebyshev polynomials and ends by presenting the different generating functions of these polynomials for simple Lie algebras of rank 2. Finally, the third chapter contains the original contribution; it presents the Hartley functions and some of their properties. It defines the generalized Chebyshev polynomials of these and also states their discrete orthogonality relations. It concludes by computing the generating functions of these polynomials for the algebras A₂, C₂ and G₂.
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