{ "id": "1103.2591", "version": "v1", "published": "2011-03-14T06:51:56.000Z", "updated": "2011-03-14T06:51:56.000Z", "title": "Derivatives of rotation number of one parameter families of circle diffeomorphisms", "authors": [ "Shigenori Matsumoto" ], "comment": "9 pages, 1 figure", "journal": "Kodai Mathematical Journal 35(2012), 115-125", "categories": [ "math.DS" ], "abstract": "We consider the rotation number $\\rho(t)$ of a diffeomorphism $f_t=R_t\\circ f$, where $R_t$ is the rotation by $t$ and $f$ is an orientation preserving $C^\\infty$ diffeomorphism of the circle $S^1$. We shall show that if $\\rho(t)$ is irrational $$\\limsup_{t'\\to t}(\\rho(t')-\\rho(t))/(t'-t)\\geq 1.$$", "revisions": [ { "version": "v1", "updated": "2011-03-14T06:51:56.000Z" } ], "analyses": { "subjects": [ "37E10", "37E45" ], "keywords": [ "rotation number", "parameter families", "circle diffeomorphisms" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1103.2591M" } } }