{ "id": "0711.4337", "version": "v2", "published": "2007-11-27T19:52:00.000Z", "updated": "2009-02-22T23:56:01.000Z", "title": "Intersection form, laminations and currents on free groups", "authors": [ "Ilya Kapovich", "Martin Lustig" ], "comment": "revised version, to appear in GAFA", "journal": "Geom. Funct. Anal. vol. 19 (2010), no. 5, pp. 1426-1467", "doi": "10.1007/s00039-009-0041-3", "categories": [ "math.GT", "math.GR" ], "abstract": "Let $F_N$ be a free group of rank $N\\ge 2$, let $\\mu$ be a geodesic current on $F_N$ and let $T$ be an $\\mathbb R$-tree with a very small isometric action of $F_N$. We prove that the geometric intersection number $$ is equal to zero if and only if the support of $\\mu$ is contained in the dual algebraic lamination $L^2(T)$ of $T$. Applying this result, we obtain a generalization of a theorem of Francaviglia regarding length spectrum compactness for currents with full support. As another application, we define the notion of a \\emph{filling} element in $F_N$ and prove that filling elements are \"nearly generic\" in $F_N$. We also apply our results to the notion of \\emph{bounded translation equivalence} in free groups.", "revisions": [ { "version": "v2", "updated": "2009-02-22T23:56:01.000Z" } ], "analyses": { "keywords": [ "free group", "intersection form", "francaviglia regarding length spectrum compactness", "dual algebraic lamination", "geometric intersection number" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0711.4337K" } } }