Digital Library of Mathematical Functions
About the Project
NIST
14 Legendre and Related FunctionsNotation

§14.1 Special Notation

(For other notation see Notation for the Special Functions.)

x, y, \tau real variables.
z=x+iy complex variable.
m, n nonnegative integers used for order and degree, respectively.
\mu, \nu general order and degree, respectively.
-\frac{1}{2}+i\tau complex degree, \tau\in\Real.
\EulerConstant Euler’s constant (§5.2(ii)).
\delta arbitrary small positive constant.
\mathop{\psi\/}\nolimits\!\left(x\right) logarithmic derivative of gamma function (§5.2(i)).
{\mathop{\psi\/}\nolimits^{{\prime}}}\!\left(x\right) \ifrac{d\mathop{\psi\/}\nolimits\!\left(x\right)}{dx} .
\mathop{\mathbf{F}\/}\nolimits\!\left(a,b;c;z\right) Olver’s scaled hypergeometric function: \ifrac{\mathop{F\/}\nolimits\!\left(a,b;c;z\right)}{\mathop{\Gamma\/}\nolimits%
\!\left(c\right)}.

Multivalued functions take their principal values (§4.2(i)) unless indicated otherwise.

The main functions treated in this chapter are the Legendre functions \mathop{\mathsf{P}_{{\nu}}\/}\nolimits\!\left(x\right), \mathop{\mathsf{Q}_{{\nu}}\/}\nolimits\!\left(x\right), \mathop{P_{{\nu}}\/}\nolimits\!\left(z\right), \mathop{Q_{{\nu}}\/}\nolimits\!\left(z\right); Ferrers functions \mathop{\mathsf{P}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right), \mathop{\mathsf{Q}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right) (also known as the Legendre functions on the cut); associated Legendre functions \mathop{P^{{\mu}}_{{\nu}}\/}\nolimits\!\left(z\right), \mathop{Q^{{\mu}}_{{\nu}}\/}\nolimits\!\left(z\right), \mathop{\boldsymbol{Q}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(z\right); conical functions \mathop{\mathsf{P}^{{\mu}}_{{-\frac{1}{2}+i\tau}}\/}\nolimits\!\left(x\right), \mathop{\mathsf{Q}^{{\mu}}_{{-\frac{1}{2}+i\tau}}\/}\nolimits\!\left(x\right), \mathop{\widehat{\mathsf{Q}}^{{\mu}}_{{-\frac{1}{2}+i\tau}}\/}\nolimits\!\left%
(x\right), \mathop{P^{{\mu}}_{{-\frac{1}{2}+i\tau}}\/}\nolimits\!\left(x\right), \mathop{Q^{{\mu}}_{{-\frac{1}{2}+i\tau}}\/}\nolimits\!\left(x\right) (also known as Mehler functions).

Among other notations commonly used in the literature Erdélyi et al. (1953a) and Olver (1997b) denote \mathop{\mathsf{P}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right) and \mathop{\mathsf{Q}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right) by \mathrm{P}_{\nu}^{\mu}(x) and \mathrm{Q}_{\nu}^{\mu}(x), respectively. Magnus et al. (1966) denotes \mathop{\mathsf{P}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right), \mathop{\mathsf{Q}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right), \mathop{P^{{\mu}}_{{\nu}}\/}\nolimits\!\left(z\right), and \mathop{Q^{{\mu}}_{{\nu}}\/}\nolimits\!\left(z\right) by P_{{\nu}}^{{\mu}}(x), Q_{{\nu}}^{{\mu}}(x), \mathfrak{P}_{{\nu}}^{{\mu}}(z), and \mathfrak{Q}_{{\nu}}^{{\mu}}(z), respectively. Hobson (1931) denotes both \mathop{\mathsf{P}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right) and \mathop{P^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right) by \mathop{P^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right); similarly for \mathop{\mathsf{Q}^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right) and \mathop{Q^{{\mu}}_{{\nu}}\/}\nolimits\!\left(x\right).