Uniqueness for some class of (nonferromagnetic) lattice systems of continuous spins

I consider lattice systems of continuous spins which correspond to the trigonometric perturbation of the Gaussian superstable two-body interactions. Using some correlation inequalities of the Ginibre type I prove uniqueness of the tempered, translationally invariant Gibbs states whenever the pressure is differentiable at the coupling constant. 14 refs. (author)