S. Shimomura, ASYMPTOTIC EXPANSIONS AND STOKES MULTIPLIERS OF THE CONFLUENT HYPERGEOMETRIC FUNCTION PHI(2),IOTA, Proceedings of the Royal Society of Edinburgh. Section A. Mathematics, 123, 1993, pp. 1165-1177
The confluent hypergeometric function Phi(2)(beta, beta', gamma , x, y
) satisfies a system of partial differential equations which possesses
the singular loci x = 0, y = 0, x - y = 0 of regular type and x = inf
inity, y = infinity of irregular type. Near x = infinity (\y\ is bound
ed) and near y = infinity (\x\ is bounded), asymptotic expansions and
Stokes multipliers of linearly independent solutions of the system are
obtained. By a connection formula, the asymptotic behaviour of Phi(2)
(beta, beta', gamma, x, y) itself is also clarified near these singula
r loci.