{ "id": "math/0404402", "version": "v3", "published": "2004-04-22T02:49:08.000Z", "updated": "2009-01-14T00:17:56.000Z", "title": "Group actions on Banach spaces and a geometric characterization of a-T-menability", "authors": [ "Piotr W. Nowak" ], "comment": "This version differs significantly from both the published version and the previous arXiv versions. The reason is a long overdue correction of implication 1=>3 in the proof of the main result. In the current version the proof is fixed but with a very different argument. I owe thanks to Cornelia Drutu for helpful correspondence which led to this update", "journal": "Topology and its Applications (2006) vol. 156 (18) pp. 3409-3412", "categories": [ "math.MG", "math.FA" ], "abstract": "We prove a geometric characterization of a-T-menability through proper, affine, isometric actions on the Banach spaces $L_p[0,1]$ for $1