小q拉盖尔多项式

小q拉盖尔多项式是一个以基本超几何函数定义的正交多项式

${\displaystyle \displaystyle p_{n}(x;a|q)={}_{2}\phi _{1}(q^{-n},0;aq;q,qx)={\frac {1}{(a^{-1}q^{-n};q)_{n}}}{}_{2}\phi _{0}(q^{-n},x^{-1};;q,x/a)}$

4th order Little q-Laguerre polynomials

极限关系

大q拉盖尔多项式→小q拉盖尔多项式

在大q拉盖尔多项式中，令${\displaystyle x\to bqx}$,并令${\displaystyle b\to \infty }$即得小q拉盖尔多项式

${\displaystyle \lim _{b\to \infty }P_{n}(bqx;a,b;q)=p_{n}(x;a|q)}$

仿射Q克拉夫楚克多项式→ 小q拉盖尔多项式：

${\displaystyle \lim _{a\to 1}=K_{n}^{aff}(q^{x-N};p,N|q)=p_{n}(q^{x};p,q)}$ 令小q拉盖尔多项式 ${\displaystyle a=q^{a}}$ ${\displaystyle x=(1-q)*x}$,然后令q→1 即得拉盖尔多项式

${\displaystyle \lim _{q\to 1}P_{a}(1-q)x;q^{a}|q)={\frac {L_{n}^{(a)}(x)}{L_{n}^{(a)}(0)}}}$

验证 9阶小q拉盖尔多项式→拉盖尔多项式

作上述代换，

${\displaystyle P_{a}(1-q)x;q^{a}|q)=1+{\frac {qx}{1-{q}^{\alpha }q}}-{\frac {x}{{q}^{8}\left(1-{q}^{\alpha }q\right)}}}$ ${\displaystyle +\left(1-{q}^{-9}\right)\left(1-{q}^{-8}\right){q}^{2}\left(1-q\right){x}^{2}\left(1-{q}^{2}\right)^{-1}\left(1-{q}^{\alpha }q\right)^{-1}\left(1-{q}^{\alpha }{q}^{2}\right)^{-1}}$${\displaystyle +\left(1-{q}^{-9}\right)\left(1-{q}^{-8}\right)\left(1-{q}^{-7}\right){q}^{3}\left(1-q\right)^{2}{x}^{3}\left(1-{q}^{2}\right)^{-1}}$${\displaystyle \left(1-{q}^{3}\right)^{-1}\left(1-{q}^{\alpha }q\right)^{-1}\left(1-{q}^{\alpha }{q}^{2}\right)^{-1}\left(1-{q}^{\alpha }{q}^{3}\right)^{-1}+\cdots }$

求q→1极限得

令a=3,得 ${\displaystyle (1-{\frac {9}{4}}x+{\frac {9}{5}}{x}^{2}-{\frac {7}{10}}{x}^{3}+{\frac {3}{20}}{x}^{4}-{\frac {3}{160}}{x}^{5}+{\frac {1}{720}}{x}^{6}-{\frac {1}{16800}}{x}^{7}+{\frac {1}{739200}}{x}^{8}-{\frac {1}{79833600}}{x}^{9})}$

另一方面

${\displaystyle {\frac {L_{n}^{(3)}(x)}{L_{n}^{(3)}(0)}}}$ =${\displaystyle (1-{\frac {9}{4}}x+{\frac {9}{5}}{x}^{2}-{\frac {7}{10}}{x}^{3}+{\frac {3}{20}}{x}^{4}-{\frac {3}{160}}{x}^{5}+{\frac {1}{720}}{x}^{6}-{\frac {1}{16800}}{x}^{7}+{\frac {1}{739200}}{x}^{8}-{\frac {1}{79833600}}{x}^{9})}$

二者显然相等 QED

图集

LITTLE Q-LAGUERRE POLYNOMIALS ABS COMPLEX 3D MAPLE PLOT

LITTLE Q-LAGUERRE POLYNOMIALS IM COMPLEX 3D MAPLE PLOT

LITTLE Q-LAGUERRE POLYNOMIALS RE COMPLEX 3D MAPLE PLOT

LITTLE Q-LAGUERRE POLYNOMIALS ABS DENSITY MAPLE PLOT

LITTLE Q-LAGUERRE POLYNOMIALS IM DENSITY MAPLE PLOT

LITTLE Q-LAGUERRE POLYNOMIALS RE DENSITY MAPLE PLOT

参考文献

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• Koornwinder, Tom H.; Wong, Roderick S. C.; Koekoek, Roelof; Swarttouw, René F., Chapter 18: Orthogonal Polynomials, Olver, Frank W. J.; Lozier, Daniel M.; Boisvert, Ronald F.; Clark, Charles W. (编), NIST Handbook of Mathematical Functions, Cambridge University Press, 2010, ISBN 978-0521192255, MR2723248
• Van Assche, Walter; Koornwinder, Tom H., Asymptotic behaviour for Wall polynomials and the addition formula for little q-Legendre polynomials, SIAM Journal on Mathematical Analysis, 1991, 22 (1): 302–311 [2024-06-17], ISSN 0036-1410, MR 1080161, doi:10.1137/0522019, （原始内容存档于2024-07-21）
• Wall, H. S., A continued fraction related to some partition formulas of Euler, The American Mathematical Monthly, 1941, 48 (2): 102–108, ISSN 0002-9890, JSTOR 2303599, MR 0003641, doi:10.1080/00029890.1941.11991074