{ "id": "1609.07805", "version": "v1", "published": "2016-09-25T21:28:33.000Z", "updated": "2016-09-25T21:28:33.000Z", "title": "$L^2$-Euler characteristics and the Thurston norm", "authors": [ "Stefan Friedl", "Wolfgang Lück" ], "comment": "42 pages", "categories": [ "math.GT" ], "abstract": "We assign to a finite $CW$-complex and an element in its first cohomology group a twisted version of the $L^2$-Euler characteristic and study its main properties. In the case of an irreducible orientable $3$-manifold with empty or toroidal boundary and infinite fundamental group we identify it with the Thurston norm. We will use the $L^2$-Euler characteristic to address the problem whether the existence of a map inducing an epimorphism on fundamental groups implies an inequality of the Thurston norms.", "revisions": [ { "version": "v1", "updated": "2016-09-25T21:28:33.000Z" } ], "analyses": { "keywords": [ "thurston norm", "euler characteristic", "first cohomology group", "infinite fundamental group", "fundamental groups implies" ], "note": { "typesetting": "TeX", "pages": 42, "language": "en", "license": "arXiv", "status": "editable" } } }