{ "id": "1908.11556", "version": "v1", "published": "2019-08-30T06:28:12.000Z", "updated": "2019-08-30T06:28:12.000Z", "title": "Anisotropic bootstrap percolation in three dimensions", "authors": [ "Daniel Blanquicett" ], "comment": "25 pages, 4 figures", "categories": [ "math.PR" ], "abstract": "Consider a $p$-random subset $A$ of initially infected vertices in the discrete cube $[L]^3$, and assume that the neighbourhood of each vertex consists of the $a_i$ nearest neighbours in the $\\pm e_i$-directions for each $i \\in \\{1,2,3\\}$, where $a_1\\le a_2\\le a_3$. Suppose we infect any healthy vertex $x\\in [L]^3$ already having $a_3+1$ infected neighbours, and that infected sites remain infected forever. In this paper we determine the critical length for percolation up to a constant factor in the exponent, for all triples $(a_1,a_2,a_3)$. To do so, we introduce a new algorithm called the beams process and prove an exponential decay property for a family of subcritical two-dimensional bootstrap processes.", "revisions": [ { "version": "v1", "updated": "2019-08-30T06:28:12.000Z" } ], "analyses": { "subjects": [ "60K35", "60C05" ], "keywords": [ "anisotropic bootstrap percolation", "dimensions", "subcritical two-dimensional bootstrap processes", "infected sites remain infected forever", "exponential decay property" ], "note": { "typesetting": "TeX", "pages": 25, "language": "en", "license": "arXiv", "status": "editable" } } }