Backward-forward SDE's and stochastic differential games

In this paper, the first part is concerned with the study of backward-forward stochastic differential equations without the non-degeneracy condition for the forward equation. We show existence and unicity of the solution to such equations under weaker monotonicity assumptions than those of Hu and Peng (1990). In a second part, we apply the results of the first part for studying the problem of existence of open-loop Nash equilibrium points for nonzero sum linear-quadratic stochastic differential games with random coefficients. We show existence, and give their expression, of such points without any limitation of the duration of the game. (C) 1998 Elsevier Science B.V. All rights reserved.