Mountford, T. S. - In: Stochastic Processes and their Applications 56 (1995) 2, pp. 185-205
We consider the behaviour of semi-oriented bootstrap percolation restricted to a finite square or torus. We prove that as the probability of initial occupancy p tends to zero, the side length required for a two-dimensional torus to have non-negligible chance of filling itself up is between for...