35.7 Gaussian Hypergeometric Function of Matrix Argument35.9 Applications

§35.8 Generalized Hypergeometric Functions of Matrix Argument

Contents

§35.8(i) Definition

Let p and q be nonnegative integers; a_{1},\dots,a_{p}\in\Complex; b_{1},\dots,b_{q}\in\Complex; -b_{j}+\tfrac{1}{2}(k+1)\notin\NatNumber, 1\leq j\leq q, 1\leq k\leq m. The generalized hypergeometric function \mathop{{{}_{{p}}F_{{q}}}\/}\nolimits with matrix argument \mathbf{T}\in\boldsymbol{\mathcal{S}}, numerator parameters a_{1},\dots,a_{p}, and denominator parameters b_{1},\dots,b_{q} is

35.8.1\mathop{{{}_{{p}}F_{{q}}}\/}\nolimits\!\left({a_{1},\dots,a_{p}\atop b_{1},\dots,b_{q}};\mathbf{T}\right)=\sum _{{k=0}}^{\infty}\frac{1}{k!}\sum _{{|\kappa|=k}}\frac{\left[a_{1}\right]_{{\kappa}}\cdots\left[a_{p}\right]_{{\kappa}}}{\left[b_{1}\right]_{{\kappa}}\cdots\left[b_{q}\right]_{{\kappa}}}\mathop{Z_{{\kappa}}\/}\nolimits\!\left(\mathbf{T}\right).

Convergence Properties

If -a_{j}+\tfrac{1}{2}(k+1)\in\NatNumber for some j,k satisfying 1\leq j\leq p, 1\leq k\leq m, then the series expansion (35.8.1) terminates.

If p\leq q, then (35.8.1) converges for all \mathbf{T}.

If p=q+1, then (35.8.1) converges absolutely for ||\mathbf{T}||<1 and diverges for ||\mathbf{T}||>1.

If p>q+1, then (35.8.1) diverges unless it terminates.

§35.8(iv) General Properties

§35.8(v) Mellin–Barnes Integrals

Multidimensional Mellin–Barnes integrals are established in Ding et al. (1996) for the functions \mathop{{{}_{{p}}F_{{q}}}\/}\nolimits and \mathop{{{}_{{p+1}}F_{{p}}}\/}\nolimits of matrix argument. A similar result for the \mathop{{{}_{{0}}F_{{1}}}\/}\nolimits function of matrix argument is given in Faraut and Korányi (1994, p. 346). These multidimensional integrals reduce to the classical Mellin–Barnes integrals (§5.19(ii)) in the special case m=1.

See also Faraut and Korányi (1994, pp. 318–340).