{ "id": "1003.3515", "version": "v1", "published": "2010-03-18T06:30:59.000Z", "updated": "2010-03-18T06:30:59.000Z", "title": "Explicit expanders with cutoff phenomena", "authors": [ "Eyal Lubetzky", "Allan Sly" ], "comment": "17 pages, 2 figures", "categories": [ "math.PR", "math.CO" ], "abstract": "The cutoff phenomenon describes a sharp transition in the convergence of an ergodic finite Markov chain to equilibrium. Of particular interest is understanding this convergence for the simple random walk on a bounded-degree expander graph. The first example of a family of bounded-degree graphs where the random walk exhibits cutoff in total-variation was provided only very recently, when the authors showed this for a typical random regular graph. However, no example was known for an explicit (deterministic) family of expanders with this phenomenon. Here we construct a family of cubic expanders where the random walk from a worst case initial position exhibits total-variation cutoff. Variants of this construction give cubic expanders without cutoff, as well as cubic graphs with cutoff at any prescribed time-point.", "revisions": [ { "version": "v1", "updated": "2010-03-18T06:30:59.000Z" } ], "analyses": { "subjects": [ "60B10", "60J10", "60G50", "05C81" ], "keywords": [ "cutoff phenomenon", "explicit expanders", "ergodic finite markov chain", "cubic expanders", "worst case initial position" ], "note": { "typesetting": "TeX", "pages": 17, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1003.3515L" } } }