{ "id": "2006.06532", "version": "v1", "published": "2020-06-11T15:43:33.000Z", "updated": "2020-06-11T15:43:33.000Z", "title": "Kotani's Theorem and the Lace Expansion", "authors": [ "Gordon Slade" ], "comment": "12 pages", "categories": [ "math.PR", "math-ph", "math.MP" ], "abstract": "In 1991, Shinichi Kotani proved a theorem giving a sufficient condition to conclude that a function $f(x)$ on ${\\mathbb Z}^d$ decays like $|x|^{-(d-2)}$ for large $x$, assuming that its Fourier transform $\\hat f(k)$ is such that $|k|^{2}\\hat f(k)$ is well behaved for $k$ near zero. We prove an extension of Kotani's Theorem and combine it with the lace expansion to give a simple proof that the critical two-point function for weakly self-avoiding walk has decay $|x|^{-(d-2)}$ in dimensions $d>4$.", "revisions": [ { "version": "v1", "updated": "2020-06-11T15:43:33.000Z" } ], "analyses": { "subjects": [ "42B05", "82B41", "82B27", "60K35" ], "keywords": [ "kotanis theorem", "lace expansion", "shinichi kotani", "fourier transform", "sufficient condition" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }