About the Project
15 Hypergeometric FunctionProperties

§15.5 Derivatives and Contiguous Functions

Contents
  1. §15.5(i) Differentiation Formulas
  2. §15.5(ii) Contiguous Functions

§15.5(i) Differentiation Formulas

Other versions of several of the identities in this subsection can be constructed with the aid of the operator identity

15.5.10 \left(z\frac{\mathrm{d}}{\mathrm{d}z}z\right)^{n}=z^{n}\frac{{\mathrm{d}}^{n}}%
{{\mathrm{d}z}^{n}}z^{n},n=1,2,3,\dots.

See Erdélyi et al. (1953a, pp. 102–103).

§15.5(ii) Contiguous Functions

The six functions F\left(a\pm 1,b;c;z\right), F\left(a,b\pm 1;c;z\right), F\left(a,b;c\pm 1;z\right) are said to be contiguous to F\left(a,b;c;z\right).

15.5.16_5 F\left(a,b;c;z\right)-F\left(a-1,b;c;z\right)-(\ifrac{b}{c})zF\left(a,b+1;c+1;%
z\right)=0,

By repeated applications of (15.5.11)–(15.5.18) any function F\left(a+k,b+\ell;c+m;z\right), in which k,\ell,m are integers, can be expressed as a linear combination of F\left(a,b;c;z\right) and any one of its contiguous functions, with coefficients that are rational functions of a,b,c, and z.