On Some Branched Continued Fraction Expansions for Horn's Hypergeometric Function H 4 (a , b ; c , d ; z 1 , z 2) Ratios.

The paper deals with the problem of representation of Horn's hypergeometric functions by branched continued fractions. The formal branched continued fraction expansions for three different Horn's hypergeometric function H 4 ratios are constructed. The method employed is a two-dimensional generalization of the classical method of constructing of Gaussian continued fraction. It is proven that the branched continued fraction, which is an expansion of one of the ratios, uniformly converges to a holomorphic function of two variables on every compact subset of some domain H , H ⊂ C 2 , and that this function is an analytic continuation of this ratio in the domain H. The application to the approximation of functions of two variables associated with Horn's double hypergeometric series H 4 is considered, and the expression of solutions of some systems of partial differential equations is indicated. [ABSTRACT FROM AUTHOR]