{ "id": "1910.02367", "version": "v1", "published": "2019-10-06T04:23:33.000Z", "updated": "2019-10-06T04:23:33.000Z", "title": "The frog model on Galton-Watson trees", "authors": [ "Marcus Michelen", "Josh Rosenberg" ], "categories": [ "math.PR" ], "abstract": "We consider an interacting particle system on trees known as the frog model: initially, a single active particle begins at the root and i.i.d. $\\mathrm{Poiss}(\\lambda)$ many inactive particles are placed at each non-root vertex. Active particles perform discrete time simple random walk and activate the inactive particles they encounter. We show that for Galton-Watson trees with offspring distributions $Z$ satisfying $\\mathbf{P}(Z \\geq 2) = 1$ and $\\mathbf{E}[Z^{4 + \\epsilon}] < \\infty$ for some $\\epsilon > 0$, there is a critical value $\\lambda_c\\in(0,\\infty)$ separating recurrent and transient regimes for almost surely every tree, thereby answering a question of Hoffman-Johnson-Junge. In addition, we also establish that this critical parameter depends on the entire offspring distribution, not just the maximum value of $Z$, answering another question of Hoffman-Johnson-Junge and showing that the frog model and contact process behave differently on Galton-Watson trees.", "revisions": [ { "version": "v1", "updated": "2019-10-06T04:23:33.000Z" } ], "analyses": { "subjects": [ "60K35" ], "keywords": [ "galton-watson trees", "frog model", "particles perform discrete time simple", "discrete time simple random walk", "perform discrete time simple random" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }