SPREAD OF DAMAGE IN THE DISCRETE N-VECTOR FERROMAGNET - EXACT RESULTS

We establish exact relations between damage spreading and relevant the rmal quantities (appropriate order parameters and correlation function s) of the ferromagnetic discrete N-vector model on an arbitrary lattic e and for arbitrary ergodic dynamics. These relations recover, as part icular cases, those already existing in the literature for the Ising, Potts and Ashkin-Teller models.