Abstract:
In this talk I will briefly introduce hierarchies of some nonlinear dispersive equations, namely KdV, mKdV and Gardner hierarchies. We will see that some of these hierarchies have soliton and breather solutions, suited to the level of the hierarchy. I will show that these soliton and breather solutions satisfy the same nonlinear ODE characterizing them for any member of the hierarchy and I will present a stability result for breather solution of some higher order mKdV equations.