{ "id": "2001.08158", "version": "v1", "published": "2020-01-22T17:28:53.000Z", "updated": "2020-01-22T17:28:53.000Z", "title": "Fixed point properties for semigroups of nonlinear mappings on unbounded sets", "authors": [ "Anthony T. -M. Lau", "Yong Zhang" ], "comment": "22 pages", "journal": "Journal of Mathematical Analysis and Applications 433 (2016), 1204-1219", "categories": [ "math.FA" ], "abstract": "A well-known result of W. Ray asserts that if $C$ is an unbounded convex subset of a Hilbert space, then there is a nonexpansive mapping $T$: $C\\to C$ that has no fixed point. In this paper we establish some common fixed point properties for a semitopological semigroup $S$ of nonexpansive mappings acting on a closed convex subset $C$ of a Hilbert space, assuming that there is a point $c\\in C$ with a bounded orbit and assuming that certain subspace of $C_b(S)$ has a left invariant mean. Left invariant mean (or amenability) is an important notion in harmonic analysis of semigroups and groups introduced by von Neumann in 1929 \\cite{Neu} and formalized by Day in 1957 \\cite{Day}. In our investigation we use the notion of common attractive points introduced recently by S. Atsushiba and W. Takahashi.", "revisions": [ { "version": "v1", "updated": "2020-01-22T17:28:53.000Z" } ], "analyses": { "subjects": [ "47H10", "47H09", "43A07", "20M30", "47H20" ], "keywords": [ "nonlinear mappings", "unbounded sets", "left invariant mean", "hilbert space", "common fixed point properties" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 22, "language": "en", "license": "arXiv", "status": "editable" } } }