The present research work proposes a new approach to the problem of finding
invariant manifolds for nonlinear real analytic dynamical systems. The for
mulation of the problem is conveniently realized through a system of singul
ar first-order quasi-linear partial differential equations (PDEs) and a rat
her general set of conditions for solvability is derived using Lyapunov's a
uxiliary theorem. The solution of the aforementioned system of PDEs is prov
en to be a locally analytic invariant manifold that under certain condition
s coincides with the stable or unstable manifold, and which can he easily c
omputed with the aid of a symbolic software package. (C) 2000 Elsevier Scie
nce B.V. All rights reserved.