{ "id": "2101.04479", "version": "v1", "published": "2021-01-12T13:53:21.000Z", "updated": "2021-01-12T13:53:21.000Z", "title": "On the generalized hypergeometric function, Sobolev orthogonal polynomials and biorthogonal rational functions", "authors": [ "Sergey M. Zagorodnyuk" ], "comment": "11 pages", "categories": [ "math.CA" ], "abstract": "It turned out that the partial sums $g_n(z) = \\sum_{k=0}^n \\frac{(a_1)_k ... (a_p)_k}{(b_1)_k ... (b_q)_k} \\frac{z^k}{k!}$, of the generalized hypergeometric series ${}_p F_q(a_1,...,a_p; b_1,...,b_q;z)$, with parameters $a_j,b_l\\in\\mathbb{C}\\backslash\\{ 0,-1,-2,... \\}$, are Sobolev orthogonal polynomials. The corresponding monic polynomials $G_n(z)$ are polynomials of $R_I$ type, and therefore they are related to biorthogonal rational functions. Polynomials $g_n$ possess a differential equation (in $z$), and a recurrence relation (in $n$). We study integral representations for $g_n$, and some other their basic properties. Partial sums of arbitrary power series with non-zero coefficients are shown to be also related to biorthogonal rational functions. We obtain a relation of polynomials $g_n(z)$ to Jacobi-type pencils and their associated polynomials.", "revisions": [ { "version": "v1", "updated": "2021-01-12T13:53:21.000Z" } ], "analyses": { "subjects": [ "42C05" ], "keywords": [ "biorthogonal rational functions", "sobolev orthogonal polynomials", "generalized hypergeometric function", "partial sums", "study integral representations" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }