11.3 Graphics11.5 Integral Representations

§11.4 Basic Properties

Contents

§11.4(i) Half-Integer Orders

§11.4(ii) Inequalities

11.4.13\mathop{\mathbf{H}_{{\nu}}\/}\nolimits\!\left(x\right)\geq 0,x>0, \nu\geq\tfrac{1}{2}.
11.4.14\mathop{\mathbf{H}_{{\nu}}\/}\nolimits\!\left(z\right)=\frac{2(\tfrac{1}{2}z)^{{\nu+1}}}{\sqrt{\pi}\mathop{\Gamma\/}\nolimits\!\left(\nu+\tfrac{3}{2}\right)}(1+\vartheta),\nu\neq-\tfrac{3}{2},-\tfrac{5}{2},-\tfrac{7}{2},\dots,

where

11.4.15|\vartheta|<\frac{2}{3}\mathop{\exp\/}\nolimits\!\left(\frac{\tfrac{1}{4}|z|^{2}}{|\nu _{0}+\tfrac{3}{2}|}-1\right),

and |\nu _{0}+\tfrac{3}{2}| is the smallest of the numbers |\nu+\tfrac{3}{2}|, |\nu+\tfrac{5}{2}|, |\nu+\tfrac{9}{2}|,\dots.

§11.4(v) Recurrence Relations and Derivatives

11.4.27\frac{d}{dz}\left(z^{\nu}\mathop{\mathbf{H}_{{\nu}}\/}\nolimits\!\left(z\right)\right)=z^{\nu}\mathop{\mathbf{H}_{{\nu-1}}\/}\nolimits\!\left(z\right),
11.4.28\frac{d}{dz}\left(z^{{-\nu}}\mathop{\mathbf{H}_{{\nu}}\/}\nolimits\!\left(z\right)\right)=\frac{2^{{-\nu}}}{\sqrt{\pi}\mathop{\Gamma\/}\nolimits\!\left(\nu+\tfrac{3}{2}\right)}-z^{{-\nu}}\mathop{\mathbf{H}_{{\nu+1}}\/}\nolimits\!\left(z\right),
11.4.29\frac{d}{dz}\left(z^{\nu}\mathop{\mathbf{L}_{{\nu}}\/}\nolimits\!\left(z\right)\right)=z^{\nu}\mathop{\mathbf{L}_{{\nu-1}}\/}\nolimits\!\left(z\right),
11.4.30\frac{d}{dz}\left(z^{{-\nu}}\mathop{\mathbf{L}_{{\nu}}\/}\nolimits\!\left(z\right)\right)=\frac{2^{{-\nu}}}{\sqrt{\pi}\mathop{\Gamma\/}\nolimits\!\left(\nu+\tfrac{3}{2}\right)}+z^{{-\nu}}\mathop{\mathbf{L}_{{\nu+1}}\/}\nolimits\!\left(z\right).
11.4.31{\cal H}_{{\nu-m}}(z)=z^{{m-\nu}}\left(\frac{1}{z}\frac{d}{dz}\right)^{m}(z^{\nu}{\cal H}_{\nu}(z)),m=1,2,3,\dots,

where {\cal H}_{\nu}(z) denotes either \mathop{\mathbf{H}_{{\nu}}\/}\nolimits\!\left(z\right) or \mathop{\mathbf{L}_{{\nu}}\/}\nolimits\!\left(z\right).

11.4.32
{\mathop{\mathbf{H}_{{0}}\/}\nolimits^{{\prime}}}\!\left(z\right)=\frac{2}{\pi}-\mathop{\mathbf{H}_{{1}}\/}\nolimits\!\left(z\right),
\frac{d}{dz}(z\mathop{\mathbf{H}_{{1}}\/}\nolimits\!\left(z\right))=z\mathop{\mathbf{H}_{{0}}\/}\nolimits\!\left(z\right),
11.4.33
{\mathop{\mathbf{L}_{{0}}\/}\nolimits^{{\prime}}}\!\left(z\right)=\frac{2}{\pi}+\mathop{\mathbf{L}_{{1}}\/}\nolimits\!\left(z\right),
\frac{d}{dz}(z\mathop{\mathbf{L}_{{1}}\/}\nolimits\!\left(z\right))=z\mathop{\mathbf{L}_{{0}}\/}\nolimits\!\left(z\right).

§11.4(vi) Derivatives with Respect to Order

For derivatives with respect to the order \nu, see Apelblat (1989) and Brychkov and Geddes (2005).

§11.4(vii) Zeros

For properties of zeros of \mathop{\mathbf{H}_{{\nu}}\/}\nolimits\!\left(x\right) see Steinig (1970).

For asymptotic expansions of zeros of \mathop{\mathbf{H}_{{0}}\/}\nolimits\!\left(x\right) see MacLeod (2002a).