{ "id": "1506.08382", "version": "v1", "published": "2015-06-28T11:10:49.000Z", "updated": "2015-06-28T11:10:49.000Z", "title": "A combinatorial identity on Galton-Watson process", "authors": [ "Linyuan Lu", "Arthur L. B. Yang" ], "comment": "9 pages", "categories": [ "math.CO" ], "abstract": "Let $f(m,c)=\\sum_{k=0}^{\\infty} (km+1)^{k-1} c^k e^{-c(km+1)/m} / (m^kk!)$. For any positive integer $m$ and positive real $c$, the identity $f(m,c)=f(1,c)^{1/m}$ arises in the random graph theory. In this paper, we present two elementary proofs of this identity: a pure combinatorial proof and a power-serial proof. We also proved that this identity holds for any positive reals $m$ and $c$.", "revisions": [ { "version": "v1", "updated": "2015-06-28T11:10:49.000Z" } ], "analyses": { "subjects": [ "05A20", "05C30", "05C80" ], "keywords": [ "combinatorial identity", "galton-watson process", "positive real", "random graph theory", "pure combinatorial proof" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }