Results 21 to 30 of about 2,128 (98)
Randers manifolds of positive constant curvature
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 18, Page 1155-1165, 2003., 2003 We prove that any simply connected and complete Riemannian manifold, on which a Randers metric of positive constant flag curvature exists, must be diffeomorphic to an odd‐dimensional sphere, provided a certain 1‐form vanishes on it.
Aurel Bejancu, Hani Reda Farran
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Ricci ϕ-invariance on almost cosymplectic three-manifolds
Open Mathematics, 2023 Let M3{M}^{3} be a strictly almost cosymplectic three-manifold whose Ricci operator is weakly ϕ\phi -invariant. In this article, it is proved that Ricci curvatures of M3{M}^{3} are invariant along the Reeb flow if and only if M3{M}^{3} is locally ...
Pan Quanxiang
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On the minimal model program for projective varieties with pseudo-effective tangent sheaf [PDF]
Épijournal de Géométrie Algébrique, 2023 In this paper, we develop a theory of pseudo-effective sheaves on normal projective varieties. As an application, by running the minimal model program, we show that projective klt varieties with pseudo-effective tangent sheaf can be decomposed into Fano ...
Shin-ichi Matsumura
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A note on Chen′s basic equality for submanifolds in a Sasakian space form
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 11, Page 711-716, 2003., 2003 It is proved that a Riemannian manifold M isometrically immersed in a Sasakian space form M˜(c) of constant φ‐sectional curvature c < 1, with the structure vector field ξ tangent to M, satisfies Chen′s basic equality if and only if it is a 3‐dimensional minimal invariant submanifold.
Mukut Mani Tripathi +2 more
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Geometry of conformal η-Ricci solitons and conformal η-Ricci almost solitons on paracontact geometry
Open Mathematics, 2022 We prove that if an η\eta -Einstein para-Kenmotsu manifold admits a conformal η\eta -Ricci soliton then it is Einstein. Next, we proved that a para-Kenmotsu metric as a conformal η\eta -Ricci soliton is Einstein if its potential vector field VV is ...
Li Yanlin +3 more
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Some submersions of CR‐hypersurfaces of Kaehler‐Einstein manifold
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 18, Page 1137-1144, 2003., 2003 The Riemannian submersions of a CR‐hypersurface M of a Kaehler‐Einstein manifold M˜ are studied. If M is an extrinsic CR‐hypersurface of M˜, then it is shown that the base space of the submersion is also a Kaehler‐Einstein manifold.
Vittorio Mangione
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Ricci-flat and Einstein pseudoriemannian nilmanifolds
Complex Manifolds, 2019 This is partly an expository paper, where the authors’ work on pseudoriemannian Einstein metrics on nilpotent Lie groups is reviewed. A new criterion is given for the existence of a diagonal Einstein metric on a nice nilpotent Lie group.
Conti Diego, Rossi Federico A.
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Foliations by minimal surfaces and contact structures on certain closed 3‐manifolds
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 21, Page 1323-1330, 2003., 2003 Let (M, g) be a closed, connected, oriented C∞ Riemannian 3‐manifold with tangentially oriented flow F. Suppose that F admits a basic transverse volume form μ and mean curvature one‐form κ which is horizontally closed. Let {X, Y} be any pair of basic vector fields, so μ(X, Y) = 1.
Richard H. Escobales Jr.
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Complex Manifolds, 2022 We give a complete classification of left invariant para-Kähler structures on four-dimensional simply connected Lie groups up to an automorphism. As an application we discuss some curvatures properties of the canonical connection associated to these ...
Mansouri M. W., Oufkou A.
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Results in Physics, 2021 Static perfect fluid spaces are of great interest in metric theories of gravitation, they being used in building realistic models of some compact objects, like neutron stars and white dwarfs.
Sharief Deshmukh +2 more
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