G. Benfatto, P. Falco, V. Matropietro
Universal Relations for Non Solvable Statistical Models
(32K, latex)

ABSTRACT.  We present the first rigorous derivation of a number of universal relations for 
a class of models with continuously varying indices (among which are 
interacting planar Ising models, quantum spin chains and 1D Fermi systems), for 
which an exact solution is not known, except in a few special cases. Most of 
these formulas were conjectured by Luther and Peschel, Kadanoff, Haldane, but 
only checked in the special solvable models; one of them, related to the 
anisotropic Ashkin-Teller model, is novel.