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We study Hermitian metrics with a Gauduchon connection being "K\"ahler-like", namely, satisfying the same symmetries for curvature as the Levi-Civita and Chern connections. In particular, we investigate $6$-dimensional solvmanifolds with…

Differential Geometry · Mathematics 2023-03-21 Daniele Angella , Antonio Otal , Luis Ugarte , Raquel Villacampa

In monograph of D. E. Blair "Riemannian geometry of contact and symplectic manifolds" and in the paper of S. Zamkovoy "Canonical connections on paracontact manifolds", the curvature identities respectively for contact and paracontact metric…

Differential Geometry · Mathematics 2012-09-24 Joanna Wełyczko

The notion of Kodaira dimension has recently been extended to general almost complex manifolds. In this paper we focus on the Kodaira dimension of almost K\"ahler manifolds, providing an explicit computation for a family of almost K\"ahler…

Differential Geometry · Mathematics 2019-09-04 Andrea Cattaneo , Antonella Nannicini , Adriano Tomassini

The largest class of Riemannian almost product manifolds, which is closed with respect to the group of the conformal transformations of the Riemannian metric, is the class of the conformal Riemannian P-manifolds. This class is an analogue…

Differential Geometry · Mathematics 2012-03-22 Dobrinka Gribacheva , Dimitar Mekerov

A recent celebrated theorem of Diverio-Trapani and Wu-Yau states that a compact K\"ahler manifold admitting a K\"ahler metric of quasi-negative holomorphic sectional curvature has an ample canonical line bundle, confirming a conjecture of…

Differential Geometry · Mathematics 2022-02-15 Yashan Zhang , Tao Zheng

We study $\mathcal D$-homothetic deformations of almost $\alpha$-Kenmotsu structures. We characterize almost contact metric manifolds which are $CR$-integrable almost $\alpha$-Kenmotsu manifolds, through the existence of a canonical linear…

Differential Geometry · Mathematics 2010-06-25 Giulia Dileo

The class W_1 of conformal Riemannian P-manifolds is the largest class of Riemannian almost product manifolds, which is closed with respect to the group of the conformal transformations of the Riemannian metric. This class is an analogue of…

Differential Geometry · Mathematics 2011-09-15 Dobrinka Gribacheva , Dimitar Mekerov

In this paper we study invariant almost Hermitian geometry on generalized flag manifolds which the isotropy representation decompose into two or three irreducible components. We will provide a classification of such flag manifolds admitting…

Differential Geometry · Mathematics 2022-11-10 Lino Grama , Ailton R. Oliveira

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

We consider the reduced twistor space $Z$ of an almost Hermitian manifold $M$, after O'Brian and Rawnsley (Ann. Global Anal. Geom., 1985). We concentrate on dimension 6. This space has a natural almost complex structure $\mathcal J$…

Differential Geometry · Mathematics 2007-05-23 Jean-Baptiste Butruille

We consider a pair of smooth manifolds, which are the counterparts in the even-dimensional and odd-dimensional cases. They are separately an almost complex manifold with Norden metric and an almost contact manifolds with B-metric,…

Differential Geometry · Mathematics 2015-05-06 Mancho Manev

In this paper we study invariant almost Hermitian geometry on generalized flag manifolds. We will focus on providing examples of K\"ahler like scalar curvature metric, that is, almost Hermitian structures $(g,J)$ satisfying $s=2s_{\rm C}$,…

Differential Geometry · Mathematics 2021-12-22 Lino Grama , Ailton R. Oliveira

We prove several K\"ahlerness criteria for compact Hermitian surfaces under semi-definiteness assumptions on natural Ricci curvatures of the Strominger-Bismut connection. The key tools for proving these results are explicit identities…

Differential Geometry · Mathematics 2026-05-27 Liangdi Zhang

On a sub-Riemannian manifold, a connection with skew-symmetric torsion is defined as the unique connection from the class of $N$-connections that has this property. Two cases are considered separately: sub-Riemannian structure of even rank,…

Differential Geometry · Mathematics 2021-08-10 Sergey V. Galaev

We study compact almost complex manifolds admitting a Hermitian metric satisfying an integral condition involving $\overline \partial$-harmonic $(0,1)$-forms. We prove that this integral condition is automatically satisfied, if the…

Differential Geometry · Mathematics 2023-02-08 Anna Fino , Nicoletta Tardini , Adriano Tomassini

Almost contact structures can be identified with sections of a twistor bundle and this allows to define their harmonicity, as sections or maps. We consider the class of nearly cosymplectic almost contact structures on a Riemannian manifold…

Differential Geometry · Mathematics 2011-09-14 E. Loubeau , E. Vergara-Diaz

On a 4-dimensional compact symplectic manifold, we consider a smooth family of compatible almost-complex structures such that at time zero the induced metric is Hermite-Einstein almost-K\"ahler metric with zero or negative Hermitian scalar…

Differential Geometry · Mathematics 2013-10-01 Mehdi Lejmi

On a Kahler manifold there is a clear connection between the complex geometry and underlying Riemannian geometry. In some ways, this can be used to characterize the Kahler condition. While such a link is not so obvious in the non-Kahler…

Differential Geometry · Mathematics 2016-06-23 Michael G. Dabkowski , Michael T. Lock

The subject of investigations are the almost hypercomplex manifolds with Hermitian and anti-Hermitian (Norden) metrics. A linear connection D is introduced such that the structure of these manifolds is parallel with respect to D and its…

Differential Geometry · Mathematics 2012-05-08 Mancho Manev , Kostadin Gribachev

An almost K\"ahler structure is {\it extremal} if the Hermitian scalar curvature is a Killing potential [29]. When the almost complex structure is integrable it coincides with extremal K\"ahler metric in the sense of Calabi [8]. We observe…

Differential Geometry · Mathematics 2018-11-15 Eveline Legendre