Contact metric manifoldsAnnals of Global Analysis and Geometry - - 1993
Themis Koufogiorgos
In this paper we study contact metric manifoldsM
2n+1(ϕ, η, ξ,g) with characteristic vector field ξ belonging to thek-nullity distribution. Moreover we prove that there exist i) nonK-contact, contact metric manifolds of dimension greater than 3 with Ricci operator commuting with ϕ and ii) 3-dimensional contact metric manifolds with non-zero constant ϕ-sectional curvature.
On the Ricci flow of homogeneous metrics on spheresAnnals of Global Analysis and Geometry - Tập 61 - Trang 499-517 - 2022
Sammy Sbiti
We study the Ricci flow of the four-parameter family of Sp
$$(n+1)$$
-invariant metrics on spheres. We determine their forward behaviour and also classify ancient solutions. In doing so, we exhibit a new one-parameter family of ancient solutions on spheres. This completes the classification of homog...... hiện toàn bộ
On disk-homogenous symmetric spacesAnnals of Global Analysis and Geometry - Tập 1 - Trang 91-104 - 1983
Oldřich Kowalski, Lieven Vanhecke
We prove a classification theorem for disk-homogeneous locally symmetric spaces.
A splitting theorem for manifolds of almost nonnegative Ricci curvatureAnnals of Global Analysis and Geometry - Tập 11 - Trang 373-385 - 1993
Mingliang Cai
Cheeger and Gromoll proved that a closed Riemannian manifold of nonnegative Ricci curvature is, up to a finite cover, diffeomorphic to a direct product of a simply connected manifold and a torus. In this paper, we extend this theorem to manifolds of almost nonnegative Ricci curvature.
On the Leibniz Cohomology of Vector FieldsAnnals of Global Analysis and Geometry - Tập 21 - Trang 177-190 - 2002
Alessandra Frabetti, Friedrich Wagemann
Gelfand and Fuks have studied the cohomology of the Lie algebra of vector fields on a manifold. In this article, we generalize their main tools to compute the Leibniz cohomology, by extending the two spectral sequences associated to the diagonal and the order filtration. In particular, we determine some new generators for the diagonal Leibniz cohomology of the Lie algebra of vector fields on the c...... hiện toàn bộ