{ "id": "1709.00769", "version": "v1", "published": "2017-09-03T21:31:52.000Z", "updated": "2017-09-03T21:31:52.000Z", "title": "The growth of Betti numbers and approximation theorems", "authors": [ "Steffen Kionke" ], "comment": "Borel seminar 2017 (14 pages)", "categories": [ "math.AT", "math.GT" ], "abstract": "These short lecture notes provide a brief introduction to the field of homology growth. They are composed out of two lectures, which I have given at the Borel seminar 2017 in Les Diablerets. We give a proof of L\\\"uck's approximation theorem, discuss generalizations and mention some related open problems. Then we discuss the growth of mod-$p$ Betti numbers, where many problems remain open. We take a closer look at the special case of $p$-adic analytic towers and discuss an approximation theorem due to Bergeron-Linnell-L\\\"uck-Sauer and Calegari-Emerton.", "revisions": [ { "version": "v1", "updated": "2017-09-03T21:31:52.000Z" } ], "analyses": { "keywords": [ "approximation theorem", "betti numbers", "short lecture notes", "problems remain open", "adic analytic towers" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }