{ "id": "1105.0825", "version": "v2", "published": "2011-05-04T13:45:32.000Z", "updated": "2011-10-06T13:08:22.000Z", "title": "\\int_x^{hx}(g^*α-α)", "authors": [ "Światosław R. Gal", "Jarek Kędra" ], "categories": [ "math.GT", "math.DS", "math.GR" ], "abstract": "Let X be a connected topological space admitting a universal cover. Let a be a degree one cohomology class on X. We define and study a two-cocycle on a group acting on X by homeomorphisms preserving the class a. We use this cocycle to investigate group actions on X. For example, we show that if an action preserves a Borel probability measure on X then the cocycle is cohomologically trivial. Under various assumptions on a homeomorphism g, we prove that it is undistorted in Homeo(X,a). In particular, we introduce a local rotation number of a homeomorphism and prove that a homeomorphism with non-constant local rotation number is undistorted.", "revisions": [ { "version": "v2", "updated": "2011-10-06T13:08:22.000Z" } ], "analyses": { "keywords": [ "non-constant local rotation number", "homeomorphism", "borel probability measure", "group actions", "action preserves" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1105.0825G" } } }