Homogeneous Riemannian Structures on Berger 3-Spheres

Abstract

13 pages.-- MSC2000 codes: 53C30, 53C25.The homogeneous Riemannian structures on the 3-dimensional Berger spheres, their corresponding reductive decompositions and the associated groups of isometries are obtained. The Berger 3-spheres are also considered as homogeneous almost contact metric manifolds.Partially supported by DGICYT, Spain, under grant BFM2002-00141 and by Xunta de Galicia under grant PGIDT01PXI20704PR.Peer reviewe