Damage spreading in the Ising model

We present two interesting results regarding damage spreading in ferromagnetic Ising models. First, we show that a damage spreading transition can occur in an Ising chain that evolves in contact with a thermal reservoir. Damage heals at low temperature and spreads at high T. The dynamic rules for the system{close_quote}s evolution for which such a transition is observed are as legitimate as the conventional rules (Glauber, Metropolis, heat bath). Our second result is that such transitions are not always in the directed percolation universality class. {copyright} {ital 1997} {ital The American Physical Society}