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In a paper by Angella, Otal, Ugarte, and Villacampa, the authors conjectured that on a compact Hermitian manifold, if a Gauduchon connection other than Chern or Strominger is K\"ahler-like, then the Hermitian metric must be K\"ahler. They…

Differential Geometry · Mathematics 2023-02-24 Quanting Zhao , Fangyang Zheng

A metric projective structure is a manifold equipped with the unparametrised geodesics of some pseudo-Riemannian metric. We make acomprehensive treatment of such structures in the case that there is a projective Weyl curvature nullity…

Differential Geometry · Mathematics 2017-11-28 A. Rod Gover , Vladimir S. Matveev

We study Hermitian metrics whose Bismut connection $\nabla^B$ satisfies the first Bianchi identity in relation to the SKT condition and the parallelism of the torsion of the Bimut connection. We obtain a characterization of complex surfaces…

Differential Geometry · Mathematics 2020-05-12 Anna Fino , Nicoletta Tardini

Let M be a hypercomplex Hermitian manifold, (M,I) the same manifold considered as a complex Hermitian with a complex structure I induced by the quaternions. The standard linear-algebraic construction produces a canonical nowhere degenerate…

Algebraic Geometry · Mathematics 2007-05-23 Misha Verbitsky

In this article, we develop an $L^{2}$-Hodge theory on complete $2n$-dimensional almost K\"{a}hler manifolds $(X,\omega)$. In the first part, we establish several identities for various Laplacians, generalized Hodge and Serre dualities, a…

Differential Geometry · Mathematics 2026-05-29 Teng Huang , Qiang Tan , Pan Zhang

In this paper we provide an explicit description of normal almost contact structures obtained from Cartan-Ehresmann connections (gauge fields) on principal $S^{1}$-bundles over complex flag manifolds. The main feature of our approach is to…

Differential Geometry · Mathematics 2019-08-08 Eder M. Correa

In this paper we introduce the twistor space of a Riemannian manifold with an even Clifford structure. This notion generalizes the twistor space of quaternion-Hermitian manifolds and weak-Spin(9) structures. We also construct almost complex…

Differential Geometry · Mathematics 2016-02-15 Gerardo Arizmendi , Charles Hadfield

A natural connection, determined by a property of its torsion tensor, is defined and it is called the second natural connection on Riemannian $\Pi$-manifold, i.e. the uniqueness of this connection is proved and a necessary and sufficient…

Differential Geometry · Mathematics 2023-02-20 Hristo Manev

We present a local classification of conformally equivalent but oppositely oriented 4-dimensional Kaehler metrics which are toric with respect to a common 2-torus action. In the generic case, these "ambitoric" structures have an intriguing…

Differential Geometry · Mathematics 2016-11-28 Vestislav Apostolov , David M. J. Calderbank , Paul Gauduchon

In this paper we study the twistor space $Z$ of an oriented Riemannian four-manifold $M$ using the moving frame approach, focusing, in particular, on the Einstein, non-self-dual setting. We prove that any general first-order linear…

Differential Geometry · Mathematics 2024-09-12 Giovanni Catino , Davide Dameno , Paolo Mastrolia

On a Hermitian manifold, the Chern connection can induce a metric connection on the background Riemannian manifold. We call the sectional curvature of the metric connection induced by the Chern connection the Chern sectional curvature of…

Differential Geometry · Mathematics 2024-03-20 Pandeng Cao , Hongjun Li

On asymptotically complex hyperbolic (ACH) Einstein manifolds, we consider a certain variational problem for almost complex structures compatible with the metric, for which the linearized Euler-Lagrange equation at K\"ahler-Einstein…

Differential Geometry · Mathematics 2021-11-10 Yoshihiko Matsumoto

We define a generalized almost para-Hermitian structure to be a commuting pair $(\mathcal{F},\mathcal{J})$ of a generalized almost para-complex structure and a generalized almost complex structure with an adequate non-degeneracy condition.…

Differential Geometry · Mathematics 2015-04-21 Izu Vaisman

Under some suitable assumptions Riemannian manifolds $(M, g, H)$ that admit a connection $\hat\nabla$ with torsion a 3-form $H$, which is both closed $d H=0$ and $\hat\nabla$-covariantly constant, are locally isometric to a product $N\times…

Differential Geometry · Mathematics 2026-05-18 Georgios Papadopoulos

Let $\nabla $ be a linear connection on an $2n$-dimensional almost anti-Hermitian manifold $M$\ equipped with an almost complex structure $J$, a pseudo-Riemannian metric $g$ and the twin metric $G=g\circ J$. In this paper, we first…

Differential Geometry · Mathematics 2019-11-15 Aydin Gezer , Hasan Cakicioglu

We obtain a closed formula for the Kaehler potential of a broad class of four-dimensional Lorentzian or Euclidean conformal "Kaehler" geometries, including the Plebanski-Demianski class and various gravitational instantons such as…

General Relativity and Quantum Cosmology · Physics 2023-05-03 Steffen Aksteiner , Bernardo Araneda

We prove that for a compact K\"ahler threefold with canonical singularities and vanishing first Chern class, the projective fibres are dense in the semiuniversal deformation space. This implies that every K\"ahler threefold of Kodaira…

Algebraic Geometry · Mathematics 2020-11-05 Patrick Graf

The main purpose of the present work is to investigate statistical manifolds endowed with almost product structures. We prove that the statistical structure of a para-K\"{a}hler-like statistical manifold of constant curvature in the…

Differential Geometry · Mathematics 2021-08-10 Gabriel-Eduard Vîlcu

In this note, we analyze the question of when will a complex nilmanifold have K\"ahler-like Strominger (also known as Bismut), Chern, or Riemannian connection, in the sense that the curvature of the connection obeys all the symmetries of…

Differential Geometry · Mathematics 2022-07-18 Quanting Zhao , Fangyang Zheng

We establish a regularity result for the metric on any 4-dimensional extremal K\"ahler manifold, and a weak compactness theorem on the space of such metrics. Specifically, the sectional curvature at a point is bounded when the quantity…

Differential Geometry · Mathematics 2011-05-11 Brian Weber