  The nonlinear Klein-Gordon equation with a different potential that satisfies
the degeneracy properties discussed in this paper possesses solitonic solutions
that interact with long-range forces. We generalize the Ginzburg-Landau
equation in such a way that the topological defects supported by this equation
present long-range interaction both in D = 1 and D > 1. Finally, we construct a
system of two equations with two complex order parameters in such a way that
the interaction forces between the topological defects decay so slowly that the
system enters the nonextensivity regime.
