18.6 Symmetry, Special Values, and Limits to Monomials18.8 Differential Equations

§18.7 Interrelations and Limit Relations

Contents

§18.7(i) Linear Transformations

Chebyshev, Ultraspherical, and Jacobi

18.7.3\mathop{T_{{n}}\/}\nolimits\!\left(x\right)=\ifrac{\mathop{P^{{(-\frac{1}{2},-\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(x\right)}{\mathop{P^{{(-\frac{1}{2},-\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(1\right)},
18.7.4\mathop{U_{{n}}\/}\nolimits\!\left(x\right)=\mathop{C^{{(1)}}_{{n}}\/}\nolimits\!\left(x\right)=\ifrac{(n+1)\mathop{P^{{(\frac{1}{2},\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(x\right)}{\mathop{P^{{(\frac{1}{2},\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(1\right)},
18.7.5\mathop{V_{{n}}\/}\nolimits\!\left(x\right)=\ifrac{(2n+1)\mathop{P^{{(\frac{1}{2},-\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(x\right)}{\mathop{P^{{(\frac{1}{2},-\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(1\right)},
18.7.6\mathop{W_{{n}}\/}\nolimits\!\left(x\right)=\ifrac{\mathop{P^{{(-\frac{1}{2},\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(x\right)}{\mathop{P^{{(-\frac{1}{2},\frac{1}{2})}}_{{n}}\/}\nolimits\!\left(1\right)}.

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.