Fox H-function

In mathematics, the Fox H-function H(x) is a generalization of the Meijer G-function introduced by Charles Fox (1961). It is defined by a Mellin–Barnes integral


H_{p,q}^{\,m,n} \!\left[ z \left| \begin{matrix}
( a_1 , A_1 ) & ( a_2 , A_2 ) & \ldots & ( a_p , A_p ) \\
( b_1 , B_1 ) & ( b_2 , B_2 ) & \ldots & ( b_q , B_q ) \end{matrix} \right. \right]
= \frac{1}{2\pi i}\int_L
\frac
{(\prod_{j=1}^m\Gamma(b_j+B_js))(\prod_{j=1}^n\Gamma(1-a_j-A_js))}
{(\prod_{j=m+1}^q\Gamma(1-b_j-B_js))(\prod_{j=n+1}^p\Gamma(a_j+A_js))}
z^{-s} \, ds

where L is a certain contour separating the poles of the two factors in the numerator.

For a further generalization of this function, useful in Physics and Statistics, see Rathie (1997).

The special case for which the Fox H-function reduces to the Meijer G-function is Aj = Bk = C, C > 0 for j = 1...p and k = 1...q (Srivastava 1984, p. 50):


H_{p,q}^{\,m,n} \!\left[ z \left| \begin{matrix}
( a_1 , C ) & ( a_2 , C ) & \ldots & ( a_p , C ) \\
( b_1 , C ) & ( b_2 , C ) & \ldots & ( b_q , C  ) \end{matrix} \right. \right]
= \frac{1}{C}
G_{p,q}^{\,m,n} \!\left( \left. \begin{matrix} a_1, \dots, a_p \\ b_1, \dots, b_q \end{matrix} \; \right| \, z^{1/C} \right).

References