Results 11 to 20 of about 1,762 (87)
Deformations of nearly G2 structures
Journal of the London Mathematical Society, Volume 104, Issue 4, Page 1795-1811, November 2021., 2021 Abstract We describe the second order obstruction to deformation for nearly G2 structures on compact manifolds. Building on work of Alexandrov and Semmelmann, this allows proving rigidity under deformation for the proper nearly G2 structure on the Aloff–Wallach space N(1,1).
Paul‐Andi Nagy, Uwe Semmelmann
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Uniform K-stability of polarized spherical varieties [PDF]
Épijournal de Géométrie Algébrique, 2023 We express notions of K-stability of polarized spherical varieties in terms of combinatorial data, vastly generalizing the case of toric varieties.
Thibaut Delcroix
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Limits of Riemannian 4‐manifolds and the symplectic geometry of their twistor spaces
Transactions of the London Mathematical Society, Volume 4, Issue 1, Page 100-109, December 2017., 2017 Abstract The twistor space of a Riemannian 4‐manifold carries two almost complex structures, J+ and J−, and a natural closed 2‐form ω. This article studies limits of manifolds for which ω tames either J+ or J−. This amounts to a curvature inequality involving self‐dual Weyl curvature and Ricci curvature, and which is satisfied, for example, by all anti‐
Joel Fine
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Toric extremal Kähler-Ricci solitons are Kähler-Einstein
Complex Manifolds, 2017 In this short note, we prove that a Calabi extremal Kähler-Ricci soliton on a compact toric Kähler manifold is Einstein. This settles for the class of toric manifolds a general problem stated by the authors that they solved only under some curvature ...
Calamai Simone, Petrecca David
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A remark on four‐dimensional almost Kähler‐Einstein manifolds with negative scalar curvature
International Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 35, Page 1837-1842, 2004., 2004 Concerning the Goldberg conjecture, we will prove a result obtained by applying the result of Iton in terms of L2‐norm of the scalar curvature.
R. S. Lemence, T. Oguro, K. Sekigawa
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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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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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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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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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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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