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16 Generalized Hypergeometric Functions & Meijer G-FunctionTwo-Variable Hypergeometric Functions

§16.16 Transformations of Variables

Contents
  1. §16.16(i) Reduction Formulas
  2. §16.16(ii) Other Transformations

§16.16(i) Reduction Formulas

16.16.1 {F_{1}}\left(\alpha;\beta,\beta^{\prime};\beta+\beta^{\prime};x,y\right)=(1-y)%
^{-\alpha}{{}_{2}F_{1}}\left({\alpha,\beta\atop\beta+\beta^{\prime}};\frac{x-y%
}{1-y}\right),
16.16.2 {F_{2}}\left(\alpha;\beta,\beta^{\prime};\gamma,\beta^{\prime};x,y\right)=(1-y%
)^{-\alpha}{{}_{2}F_{1}}\left({\alpha,\beta\atop\gamma};\frac{x}{1-y}\right),
16.16.3 {F_{2}}\left(\alpha;\beta,\beta^{\prime};\gamma,\alpha;x,y\right)=(1-y)^{-%
\beta^{\prime}}{F_{1}}\left(\beta;\alpha-\beta^{\prime},\beta^{\prime};\gamma;%
x,\frac{x}{1-y}\right),
16.16.4 {F_{3}}\left(\alpha,\gamma-\alpha;\beta,\beta^{\prime};\gamma;x,y\right)=(1-y)%
^{-\beta^{\prime}}{F_{1}}\left(\alpha;\beta,\beta^{\prime};\gamma;x,\frac{y}{y%
-1}\right),
16.16.5 {F_{3}}\left(\alpha,\gamma-\alpha;\beta,\gamma-\beta;\gamma;x,y\right)=(1-y)^{%
\alpha+\beta-\gamma}{{}_{2}F_{1}}\left({\alpha,\beta\atop\gamma};x+y-xy\right),
16.16.5_5 {F_{4}}\left(\alpha,\beta;\gamma,\beta;x(1-y),y(1-x)\right)=(1-x)^{-\alpha}(1-%
y)^{-\alpha}{F_{1}}\left(\alpha;\gamma-\beta,\alpha-\gamma+1;\gamma;\frac{x}{x%
-1},\frac{xy}{(1-x)(1-y)}\right),
16.16.6 {F_{4}}\left(\alpha,\beta;\gamma,\alpha+\beta-\gamma+1;x(1-y),y(1-x)\right)={{%
}_{2}F_{1}}\left({\alpha,\beta\atop\gamma};x\right){{}_{2}F_{1}}\left({\alpha,%
\beta\atop\alpha+\beta-\gamma+1};y\right).

See Erdélyi et al. (1953a, §5.10) for these and further reduction formulas. An extension of (16.16.6) is given by

see Burchnall and Chaundy (1940, 1941).

§16.16(ii) Other Transformations

16.16.8 {F_{1}}\left(\alpha;\beta,\beta^{\prime};\gamma;x,y\right)=(1-x)^{-\beta}(1-y)%
^{-\beta^{\prime}}{F_{1}}\left(\gamma-\alpha;\beta,\beta^{\prime};\gamma;\frac%
{x}{x-1},\frac{y}{y-1}\right)=(1-x)^{-\alpha}{F_{1}}\left(\alpha;\gamma-\beta-%
\beta^{\prime},\beta^{\prime};\gamma;\frac{x}{x-1},\frac{y-x}{1-x}\right),
16.16.9 {F_{2}}\left(\alpha;\beta,\beta^{\prime};\gamma,\gamma^{\prime};x,y\right)=(1-%
x)^{-\alpha}{F_{2}}\left(\alpha;\gamma-\beta,\beta^{\prime};\gamma,\gamma^{%
\prime};\frac{x}{x-1},\frac{y}{1-x}\right),
16.16.10 {F_{4}}\left(\alpha,\beta;\gamma,\gamma^{\prime};x,y\right)=\frac{\Gamma\left(%
\gamma^{\prime}\right)\Gamma\left(\beta-\alpha\right)}{\Gamma\left(\gamma^{%
\prime}-\alpha\right)\Gamma\left(\beta\right)}(-y)^{-\alpha}{F_{4}}\left(%
\alpha,\alpha-\gamma^{\prime}+1;\gamma,\alpha-\beta+1;\frac{x}{y},\frac{1}{y}%
\right)+\frac{\Gamma\left(\gamma^{\prime}\right)\Gamma\left(\alpha-\beta\right%
)}{\Gamma\left(\gamma^{\prime}-\beta\right)\Gamma\left(\alpha\right)}(-y)^{-%
\beta}{F_{4}}\left(\beta,\beta-\gamma^{\prime}+1;\gamma,\beta-\alpha+1;\frac{x%
}{y},\frac{1}{y}\right).

For quadratic transformations of Appell functions see Carlson (1976).