Diffusion percolation. I. Infinite time limit and bootstrap percolation

Several models for the dynamic growth of percolation clusters, or 'diffusion percolation' (DP), are introduced and analysed. In these models a random walker (an 'ant') walks on percolation clusters (which are occupied with initial site concentration, p_i). The 'ant' is allowed to step off such clusters and add new sites to them if certain conditions are met. Some of these models are shown to have a one-to-one correspondence with models of bootstrap percolation (BP), in which sites which do not have a required number of neighbours are successively culled. Two new percolation thresholds have been calculated for two diffusion percolation models on the square lattice.