{ "id": "1609.07043", "version": "v1", "published": "2016-09-22T16:00:15.000Z", "updated": "2016-09-22T16:00:15.000Z", "title": "On percolation critical probabilities and unimodular random graphs", "authors": [ "Dorottya Beringer", "Gábor Pete", "Ádám Timár" ], "comment": "25 pages", "categories": [ "math.PR" ], "abstract": "We investigate generalisations of the classical percolation critical probabilities $p_c$, $p_T$ and the critical probability $\\tilde{p_c}$ defined by Duminil-Copin and Tassion (2015) to bounded degree unimodular random graphs. We further examine Schramm's conjecture in the case of unimodular random graphs: does $p_c(G_n)$ converge to $p_c(G)$ if $G_n\\to G$ in the local weak sense? Among our results are the following: 1. $p_c=\\tilde{p_c}$ holds for bounded degree unimodular graphs. However, there are unimodular graphs with sub-exponential volume growth and $p_T < p_c$; i.e., the classical sharpness of phase transition does not hold. 2. We give conditions which imply the inequality $\\liminf p_c(G_n) \\geq p_c(\\lim G_n)$. 3. There are sequences of unimodular graphs such that $G_n\\to G$ but $p_c(G)>\\lim p_c(G_n)$ or $p_c(G)<\\lim p_c(G_n)<1$. As a corollary to our positive results, we show that for any transitive graph with sub-exponential volume growth there is a sequence $T_n$ of large girth bi-Lipschitz invariant subgraphs such that $p_c(T_n)\\to 1$. It remains open whether this holds whenever the transitive graph has cost 1.", "revisions": [ { "version": "v1", "updated": "2016-09-22T16:00:15.000Z" } ], "analyses": { "keywords": [ "percolation critical probabilities", "critical probability", "unimodular graphs", "sub-exponential volume growth", "large girth bi-lipschitz invariant subgraphs" ], "note": { "typesetting": "TeX", "pages": 25, "language": "en", "license": "arXiv", "status": "editable" } } }