Digital Library of Mathematical Functions
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18 Orthogonal PolynomialsClassical Orthogonal Polynomials

§18.7 Interrelations and Limit Relations

Contents

§18.7(i) Linear Transformations

Chebyshev, Ultraspherical, and Jacobi

See also (18.9.9)–(18.9.12).

Hermite

18.7.11\mathop{\mathit{He}_{{n}}\/}\nolimits\!\left(x\right)=2^{{-\frac{1}{2}n}}%
\mathop{H_{{n}}\/}\nolimits\!\left(2^{{-\frac{1}{2}}}x\right),
18.7.12\mathop{H_{{n}}\/}\nolimits\!\left(x\right)=2^{{\frac{1}{2}n}}\mathop{\mathit{%
He}_{{n}}\/}\nolimits\!\left(2^{{\frac{1}{2}}}x\right).

§18.7(ii) Quadratic Transformations

18.7.13\frac{\mathop{P^{{(\alpha,\alpha)}}_{{2n}}\/}\nolimits\!\left(x\right)}{%
\mathop{P^{{(\alpha,\alpha)}}_{{2n}}\/}\nolimits\!\left(1\right)}=\frac{%
\mathop{P^{{(\alpha,-\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(2x^{2}-1\right)}{%
\mathop{P^{{(\alpha,-\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(1\right)},
18.7.14\frac{\mathop{P^{{(\alpha,\alpha)}}_{{2n+1}}\/}\nolimits\!\left(x\right)}{%
\mathop{P^{{(\alpha,\alpha)}}_{{2n+1}}\/}\nolimits\!\left(1\right)}=\frac{x%
\mathop{P^{{(\alpha,\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(2x^{2}-1\right)}{%
\mathop{P^{{(\alpha,\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(1\right)}.

§18.7(iii) Limit Relations

Laguerre \to Hermite

See Figure 18.21.1 for the Askey schematic representation of most of these limits.