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326 W. Koepf, D. Schmersau / Appl. Math. Comput. 128 (2002) 303–327<br />

Using our implementation, these results are obtained by<br />

> RE :¼ pðnþ2Þ x pðnþ1Þþalpha q^n ðq^ðnþ1Þ 1Þ pðnÞ¼0;<br />

RE :¼ pðn þ 2Þ xpðn þ 1Þþaq n ðq ðnþ1Þ<br />

1ÞpðnÞ ¼0<br />

> REtoqDE(RE,p(n),q,x);<br />

Warning: parameters have the values<br />

fe ¼ 0; a ¼ dq þ d; c ¼ aqd þ ad; d ¼ d; b ¼ 0g<br />

ðx 2<br />

"<br />

þ aÞDq Dq pðn; xÞ; 1<br />

; x ; q; x<br />

q<br />

xDqðpðn; xÞ; q; xÞ<br />

q 1<br />

þ qð 1 þ qnÞpðn; xÞ<br />

ðq 1Þ 2 qn ¼ 0; qðqxÞ<br />

qðxÞ ¼<br />

a<br />

q2x2 #<br />

knþ1<br />

; ¼ 1<br />

þ a kn<br />

:<br />

Note that q-<strong>polynomial</strong>s are not accessible with Koornwinder–Swarttouw’s<br />

rec2ortho.<br />

Note: The Maple implementation retode, <strong>and</strong> a worksheet retode.mws<br />

with the examples of this paper can be obtained from http://www.mathematik.<br />

uni-kassel.de/ koepf/Publikationen.<br />

Acknowledgements<br />

The first named author thanks Tom Koornwinder <strong>and</strong> Rene Swarttouw for<br />

helpful discussions on <strong>their</strong> implementation rec2ortho [12]. Examples 2 <strong>and</strong><br />

4 given by recurrence equation (31) were provided by them. Thanks to the<br />

support of <strong>their</strong> institutions I had a very pleasant <strong>and</strong> interesting visit at the<br />

Amsterdam universities in August 1996.<br />

References<br />

[1] M. Abramowitz, I.A. Stegun, H<strong>and</strong>book of Mathematical Functions, Dover, New York, 1964.<br />

[2] W.A. Al-Salam, The Bessel <strong>polynomial</strong>s, Duke Math. J. 24 (1957) 529–545.<br />

[3] S. Bochner, €Uber Sturm–Liouvillesche Polynomsysteme, Math. Z. 29 (1929) 730–736.<br />

[4] W.C. Brenke, On <strong>polynomial</strong> solutions of a class of linear differential <strong>equations</strong> of the second<br />

order, Bull. Amer. Math. Soc. 36 (1930) 77–84.<br />

[5] T.S. Chihara, An Introduction to Orthogonal Polynomials, Gordon <strong>and</strong> Breach, NewYork,<br />

1978.<br />

[6] W. Hahn, € Uber Orthogonalpolynome, die q-Differenzengleichungen, Math. Nachr. 2 (1949) 4–<br />

34.<br />

[7] R. Koekoek, R.F. Swarttouw, The Askey-scheme of hypergeometric <strong>orthogonal</strong> <strong>polynomial</strong>s<br />

<strong>and</strong> its q-analogue, Report 98-17, Delft University of Technology, Faculty of Information<br />

Technology <strong>and</strong> Systems, Department of Technical Mathematics <strong>and</strong> Informatics, Delft;<br />

electronic version available at http://aw.twi.tudelft.nl/ koekoek/research.html, 1998.

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