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A locally conformal SKT (shortly LCSKT) structure is a Hermitian structure $(J, g)$ whose Bismut torsion 3-form $H$ satisfies the condition $dH = \alpha \wedge H$, for some closed non-zero 1-form $\alpha$. This condition was introduced in…

Differential Geometry · Mathematics 2022-12-23 Louis-Brahim Beaufort , Anna Fino

An example of a four-dimensional special complex manifold with Norden metric of constant holomorphic sectional curvature is constructed via a two-parametric family of solvable Lie algebras. The curvature properties of the obtained manifold…

Differential Geometry · Mathematics 2011-04-29 Marta Teofilova

We study complex non-K\"ahler manifolds with Hermitian metrics being locally conformal to metrics with special cohomological properties. In particular, we provide examples where the existence of locally conformal holomorphic-tamed…

Differential Geometry · Mathematics 2016-08-04 Daniele Angella , Luis Ugarte

There are studied Lie groups considered as almost hypercomplex Hermitian-Norden manifolds, which are integrable and have the lowest dimension four. It is established a correspondence of the derived Lie algebras of types of invariant…

Differential Geometry · Mathematics 2019-03-22 Hristo Manev

Object of investigation are almost hypercomplex manifolds with Hermitian-Norden metrics of the lowest dimension. The considered manifolds are constructed on 4-dimensional Lie groups. It is established a relation between the classes of a…

Differential Geometry · Mathematics 2021-03-16 Hristo Manev

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

A study is made of real Lie algebras admitting a hypersymplectic structure, and we provide a method to construct such hypersymplectic Lie algebras. We use this method in order to obtain the classification of all hypersymplectic structures…

Differential Geometry · Mathematics 2007-05-23 Adrian Andrada

KT-geometry is the geometry of a Hermitian connection whose torsion is a 3-form. HKT-geometry is the geometry of a hyper-Hermitian connection whose torsion is a 3-form. We identify non-trivial conditions for a reduction theory for these…

Differential Geometry · Mathematics 2009-10-09 Gueo Grantcharov , George Papadopoulos , Yat Sun Poon

We investigate harmonic forms of geometrically formal metrics, which are defined as those having the exterior product of any two harmonic forms still harmonic. We prove that a formal Sasakian metric can exist only on a real cohomology…

Differential Geometry · Mathematics 2014-02-26 Jean-Francois Grosjean , Paul-Andi Nagy

Let $ G $ be a connected Lie group with real Lie algebra $ \mathfrak{g}$. Suppose $G$ is also a complex manifold. We obtain explicit holomorphic sectional and bisectional curvature formulas of left-invariant strongly pseudoconvex complex…

Differential Geometry · Mathematics 2026-01-01 Kuankuan Luo , Wei Xiao , Chunping Zhong

We review the theory of quaternionic Kahler and hyperkahler structures. Then we consider the tangent bundle of a Riemannian manifold M with a metric connection D (with torsion) and with its well estabilished canonical complex structure.…

Differential Geometry · Mathematics 2011-12-15 Rui Albuquerque

A complex symplectic structure on a Lie algebra $\lie h$ is an integrable complex structure $J$ with a closed non-degenerate $(2,0)$-form. It is determined by $J$ and the real part $\Omega$ of the $(2,0)$-form. Suppose that $\lie h$ is a…

Differential Geometry · Mathematics 2011-05-25 Richard Cleyton , Gabriela P. Ovando , Yat Sun Poon

We give a classification of toric, Hermitian, Ricci flat, ALF Riemannian metrics in dimension 4, including metrics with conical singularities. The only smooth examples are on one hand the hyperKaehler ALF metrics, on the other hand, the…

Differential Geometry · Mathematics 2022-11-30 Olivier Biquard , Paul Gauduchon

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 study metric and cohomological properties of Oeljeklaus-Toma manifolds. In particular, we describe the structure of the double complex of differential forms and its Bott-Chern cohomology and we characterize the existence of pluriclosed…

Differential Geometry · Mathematics 2023-12-25 Danielle Angella , Arturas Dubickas , Alexandra Otiman , Jonas Stelzig

This paper classifies Hermitian structures on 6-dimensional nilmanifolds M=G/L for which the fundamental 2-form is d d-bar closed, a condition that is shown to depend only on the underlying complex structure J of M. The space of such J is…

Differential Geometry · Mathematics 2013-10-15 Anna Fino , Maurizio Parton , Simon Salamon

We study the six-dimensional solvmanifolds that admit complex structures of splitting type classifying the underlying solvable Lie algebras. In particular, many complex structures of this type exist on the Nakamura manifold $X$, and they…

Differential Geometry · Mathematics 2017-12-12 Daniele Angella , Antonio Otal , Luis Ugarte , Raquel Villacampa

In the present paper, we study compact complex manifolds admitting a Hermitian metric which is SKT and CYT and whose Bismut torsion is parallel. We first obtain a characterization of the universal cover of such manifolds as a product of a…

Differential Geometry · Mathematics 2024-11-20 Beatrice Brienza , Anna Fino , Gueo Grantcharov

Let $(M, \Omega)$ be a holomorphically symplectic manifold equipped with a holomorphic Lagrangian fibration $\pi: M \to B$, and $\eta$ a closed $(1,1)$-form on $B$. Then $\Omega+ \pi^* \eta$ is a holomorphically symplectic form on a complex…

Algebraic Geometry · Mathematics 2025-04-22 Andrey Soldatenkov , Misha Verbitsky

Let $(\acute{N},g,\nabla )$\ be a $2n$-dimensional quasi-statistical manifold that admits a pseudo-Riemannian metric $g$ (or $h)$ and a linear connection $\nabla $ with torsion. This paper aims to study an almost Hermitian structure $(g,L)$…

Differential Geometry · Mathematics 2023-07-31 Aydin Gezer , Busra Aktas , Olgun Durmaz