  This article develops duality principles applicable to the Ginzburg-Landau
system in superconductivity. The main results are obtained through standard
tools of convex analysis, functional analysis, calculus of variations and
duality theory. In the second section, we present the general result for the
case including a magnetic field and the respective magnetic potential in a
local extremal context. Finally, in the last section we develop some global
existence results for a model in elasticity.
