On the orthogonality of partial sums of the generalized hypergeometric series

UDC 517.587 It turns out that the partial sums $g_n(z)=\displaystyle\sum\nolimits_{k=0}^n\dfrac{(a_1)_k\ldots(a_p)_k}{(b_1)_k\ldots(b_q)_k}\,\dfrac{z^k}{k!}$ of the generalized hypergeometric series ${}_p F_q(a_1,\ldots,a_p;b_1,\ldots,b_q;z)$ with parameters $a_j, b_l\in\mathbb{C}\backslash\{0,-1,-2...

Повний опис

Збережено в:
Бібліографічні деталі
Дата:2022
Автори: Zagorodnyuk, S. M., Загороднюк , С. М.
Формат: Стаття
Мова:Українська
Опубліковано: Institute of Mathematics, NAS of Ukraine 2022
Онлайн доступ:https://umj.imath.kiev.ua/index.php/umj/article/view/6989
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Назва журналу:Ukrains’kyi Matematychnyi Zhurnal
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Репозитарії

Ukrains’kyi Matematychnyi Zhurnal
Опис
Резюме:UDC 517.587 It turns out that the partial sums $g_n(z)=\displaystyle\sum\nolimits_{k=0}^n\dfrac{(a_1)_k\ldots(a_p)_k}{(b_1)_k\ldots(b_q)_k}\,\dfrac{z^k}{k!}$ of the generalized hypergeometric series ${}_p F_q(a_1,\ldots,a_p;b_1,\ldots,b_q;z)$ with parameters $a_j, b_l\in\mathbb{C}\backslash\{0,-1,-2,\ldots\}$ are Sobolev orthogonal polynomials.The corresponding monic polynomials $G_n(z)$ are $R_I$-type polynomials, and therefore, they are related to biorthogonal rational functions.The polynomials $g_n$ satisfy a differential equation (in $z$) and a recurrence relation (in $n$).In this paper, we study the integral representations for $g_n$ and their basic properties.It is shown that partial sums of arbitrary power series with non-zero coefficients are also related to biorthogonal rational functions.For polynomials $g_n(z),$ we obtain a relation to Jacobi-type pencils and their associated polynomials.
DOI:10.37863/umzh.v74i1.6989