{ "id": "1909.04649", "version": "v1", "published": "2019-09-10T17:49:09.000Z", "updated": "2019-09-10T17:49:09.000Z", "title": "Bootstrap percolation in Ore-type graphs", "authors": [ "Alexandra Wesolek" ], "comment": "26 pages, 5 figures", "categories": [ "math.CO" ], "abstract": "The $r$-neighbour bootstrap process describes an infection process on a graph, where we start with a set of initially infected vertices and an uninfected vertex becomes infected as soon as it has $r$ infected neighbours. An inital set of infected vertices is called percolating if at the end of the bootstrap process all vertices are infected. We give Ore-type conditions that guarantee the existence of a small percolating set of size $l\\leq 2r-2$ if the number of vertices $n$ of our graph is sufficiently large: if $l\\geq r$ and satisfies $2r \\geq l+2 \\lfloor \\sqrt{2(l-r)+0.25}+2.5 \\rfloor-1$ then there exists a percolating set of size $l$ for every graph in which any two non-adjacent vertices $x$ and $y$ satisfy $deg(x)+deg(y) \\geq n+4r-2l-2\\lfloor\\sqrt{2(l-r)+0.25}+2.5 \\rfloor-1$ and if $l$ is larger with $l\\leq 2r-2$ there exists a percolating set of size $l$ if $deg(x)+deg(y) \\geq n+2r-l-2$. Our results extend the work of Gunderson, who showed that a graph with minimum degree $\\lfloor n/2 \\rfloor+r-3$ has a percolating set of size $r \\geq 4$. We also give bounds for arbitrarily large $l$ in the minimum degree setting.", "revisions": [ { "version": "v1", "updated": "2019-09-10T17:49:09.000Z" } ], "analyses": { "subjects": [ "05C35", "05C99", "G.2.2" ], "keywords": [ "bootstrap percolation", "ore-type graphs", "percolating set", "minimum degree", "neighbour bootstrap process" ], "note": { "typesetting": "TeX", "pages": 26, "language": "en", "license": "arXiv", "status": "editable" } } }