Results 11 to 20 of about 1,769 (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
wiley +1 more source
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.
doaj +1 more source
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
doaj +1 more source
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
wiley +1 more source
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.
doaj +1 more source
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
doaj +1 more source
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
wiley +1 more source
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
wiley +1 more source
G2-metrics arising from non-integrable special Lagrangian fibrations
Complex Manifolds, 2019 We study special Lagrangian fibrations of SU(3)-manifolds, not necessarily torsion-free. In the case where the fiber is a unimodular Lie group G, we decompose such SU(3)-structures into triples of solder 1-forms, connection 1-forms and equivariant 3 × 3 ...
Chihara Ryohei
doaj +1 more source
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
doaj +1 more source