We study a system of
layers with a Kac horizontal interaction of parameter
and a Kac vertical
interaction of parameter
.
We shall prove that the limit free energy functional is the rate function
of the large deviations of the Gibbs measure (of a canonical constrained
magnetization). The limit free energy functional is achieved as a
-limit
for
for magnetizations with fixed average. Among all such magnetizations there exists a
quasiconstant magnetization that minimizes the energy.