  Multi-soliton solutions, i.e. solutions behaving as the sum of N given
solitons as $t\to +\infty$, were constructed in previous works for the L2
critical and subcritical (NLS) and (gKdV) equations.
  In this paper, we extend the construction of multi-soliton solutions to the
L2 supercritical case both for (gKdV) and (NLS) equations, using a topological
argument to control the direction of instability.
