Affine q-Krawtchouk polynomials

In mathematics, the affine q-Krawtchouk polynomials are a family of basic hypergeometric orthogonal polynomials in the basic Askey scheme, introduced by Carlitz and Hodges. Roelof Koekoek, Peter A. Lesky, and René F. Swarttouw (2010, 14) give a detailed list of their properties.

Definition

The polynomials are given in terms of basic hypergeometric functions by ^[1]

${\displaystyle K_{n}^{\text{aff}}(q^{-x};p;N;q)={}_{3}\phi _{2}\left({\begin{matrix}q^{-n},0,q^{-x}\\pq,q^{-N}\end{matrix}};q,q\right),\qquad n=0,1,2,\ldots ,N.}$

Relation to other polynomials

affine q-Krawtchouk polynomials → little q-Laguerre polynomials：

${\displaystyle \lim _{a\to 1}=K_{n}^{\text{aff}}(q^{x-N};p,N\mid q)=p_{n}(q^{x};p,q)}$.