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Rogers polynomials

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(Redirected from Rogers–Askey–Ismail polynomial) Family of orthogonal polynomials Not to be confused with Rogers–Szegő polynomials.

In mathematics, the Rogers polynomials, also called Rogers–Askey–Ismail polynomials and continuous q-ultraspherical polynomials, are a family of orthogonal polynomials introduced by Rogers (1892, 1893, 1894) in the course of his work on the Rogers–Ramanujan identities. They are q-analogs of ultraspherical polynomials, and are the Macdonald polynomials for the special case of the A1 affine root system (Macdonald 2003, p.156).

Askey & Ismail (1983) and Gasper & Rahman (2004, 7.4) discuss the properties of Rogers polynomials in detail.

Definition

The Rogers polynomials can be defined in terms of the q-Pochhammer symbol and the basic hypergeometric series by

C n ( x ; β | q ) = ( β ; q ) n ( q ; q ) n e i n θ 2 ϕ 1 ( q n , β ; β 1 q 1 n ; q , q β 1 e 2 i θ ) {\displaystyle C_{n}(x;\beta |q)={\frac {(\beta ;q)_{n}}{(q;q)_{n}}}e^{in\theta }{}_{2}\phi _{1}(q^{-n},\beta ;\beta ^{-1}q^{1-n};q,q\beta ^{-1}e^{-2i\theta })}

where x = cos(θ).

References

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