INSTABILITY IN THE PRESENCE OF AN INDEFINITE CONSERVATION LAW
Abstract
Consider a C1 vector field X on a finite-dimensional manifold M and xe an equilibrium point for the dynamics . We will prove that if I is a C2 constant of motion for X such that xe is also a critical point of I, then
is a constant of motion for the linearized system
. As a consequence we will give an instability result under the condition that
is an indefinite quadratic form. If xe is not a critical point of I, then we obtain
as a constant of motion for the linearized system.