{ "id": "math/0611256", "version": "v1", "published": "2006-11-09T06:35:36.000Z", "updated": "2006-11-09T06:35:36.000Z", "title": "Invariant Subspaces for Operators in a General II_1-factor", "authors": [ "Uffe Haagerup", "Hanne Schultz" ], "comment": "83 pages", "categories": [ "math.OA", "math.FA" ], "abstract": "It is shown that to every operator T in a general von Neumann factor M of type II_1 and to every Borel set B in the complex plane, one can associate a largest, closed, T-invariant subspace, K = K_T(B), affiliated with M, such that the Brown measure of T|_K is concentrated on B. Moreover, K is T-hyperinvariant, and the Brown measure of (1-P_K)T|_(1-P_K)(H) is concentrated on C\\B. In particular, if T has a Brown measure which is not concentrated on a singleton, then there exists a non-trivial, closed, T-hyperinvariant subspace. Furthermore, it is shown that for every T in M, the limit A=\\lim_{n\\to\\infty}[(T^n)* T^n]^{1/2n} exists in the strong operator topology and K_T(\\bar{B(0,r)})=1_{[0,r]}(A), r>0.", "revisions": [ { "version": "v1", "updated": "2006-11-09T06:35:36.000Z" } ], "analyses": { "subjects": [ "47A15", "47C15", "46L54" ], "keywords": [ "invariant subspaces", "brown measure", "general von neumann factor", "strong operator topology", "t-invariant subspace" ], "note": { "typesetting": "TeX", "pages": 83, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2006math.....11256H" } } }