{ "id": "1502.04482", "version": "v1", "published": "2015-02-16T10:12:45.000Z", "updated": "2015-02-16T10:12:45.000Z", "title": "A new proof of Friedman's second eigenvalue Theorem and its extension to random lifts", "authors": [ "Charles Bordenave" ], "comment": "39 pages", "categories": [ "math.CO", "math.PR" ], "abstract": "It was conjectured by Alon and proved by Friedman that a random $d$-regular graph has nearly the largest possible spectral gap, more precisely, the largest absolute value of the non-trivial eigenvalues of its adjacency matrix is at most $2\\sqrt{d-1} +o(1)$ with probability tending to one as the size of the graph tends to infinity. We give a new proof of this statement. We also study related questions on random $n$-lifts of graphs and improve a recent result by Friedman and Kohler.", "revisions": [ { "version": "v1", "updated": "2015-02-16T10:12:45.000Z" } ], "analyses": { "subjects": [ "05C80", "05C50" ], "keywords": [ "friedmans second eigenvalue theorem", "random lifts", "largest absolute value", "spectral gap", "regular graph" ], "note": { "typesetting": "TeX", "pages": 39, "language": "en", "license": "arXiv", "status": "editable" } } }