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In this paper, we study MRC fibrations of compact K\"ahler manifolds with partially semi-positive curvature. We first prove that a compact K\"ahler manifold is rationally connected if its tangent bundle is BC-$p$ positive for all $1\leq…

Differential Geometry · Mathematics 2026-03-09 Shiyu Zhang , Xi Zhang

A Cartan manifold is a smooth manifold M whose slit cotangent bundle T*M0 is endowed with a regular Hamiltonian K which is positively homogeneous of degree 2 in momenta. The Hamiltonian K defines a (pseudo)-Riemannian metric gij in the…

Mathematical Physics · Physics 2012-10-20 E. Peyghan , A. Tayebi , A. Ahmadi

We investigate T-duality transformation on an almost bi-hermitian space with torsion. By virtue of the Buscher rule, we completely describe not only the covariant derivative of geometrical objects but also the Nijenhuis tensor. We apply…

High Energy Physics - Theory · Physics 2025-03-24 Tetsuji Kimura , Shin Sasaki , Kenta Shiozawa

For a closed smooth manifold $M$ admitting a symplectic structure, we define a smooth topological invariant $Z(M)$ using almost-K\"ahler metrics, i.e. Riemannian metrics compatible with symplectic structures. We also introduce $Z(M,…

Differential Geometry · Mathematics 2014-09-19 Jongsu Kim , Chanyoung Sung

We introduce the notion of even Clifford structures on Riemannian manifolds, a framework generalizing almost Hermitian and quaternion-Hermitian geometries. We give the complete classification of manifolds carrying parallel even Clifford…

Differential Geometry · Mathematics 2019-01-08 Andrei Moroianu , Uwe Semmelmann

It is observed that on a compact almost complex Calabi-Yau with torsion 6-manifold the Nijenhuis tensor is parallel with respect to the torsion connection. If the torsion is closed then the space is a compact generalized gradient Ricci…

Differential Geometry · Mathematics 2024-08-21 Stefan Ivanov , Nikola Stanchev

There is considered a connection with skew symmetric torsion on a quasi-K\"ahler manifold with Norden metric. Some necessary and sufficient conditions are derived for the corresponding curvature tensor to be K\"ahlerian. In the case when…

Differential Geometry · Mathematics 2009-07-14 Dimitar Mekerov

This survey article mainly addresses to graduate students and young researchers in complex geometry willing to enter the beautiful word of connections between curvature and Kobayashi hyperbolicity. It is a detailed account of a recent…

Differential Geometry · Mathematics 2020-12-16 Simone Diverio

This paper presents an investigation of the relation between some positivity of the curvature and the finiteness of fundamental groups in semi-Riemannian geometry. We consider semi-Riemannian submersions $\pi : (E, g) \rightarrow (B,…

Differential Geometry · Mathematics 2021-04-27 Jun-ichi Mukuno

In this paper we consider left-invariant pseudo-K\"{a}hler structures on six-dimensional nilpotent Lie algebras. The explicit expressions of the canonical complex structures are calculated, and the curvature properties of the associated…

Differential Geometry · Mathematics 2013-11-15 N. K. Smolentsev

We investigate 3-dimensional almost Kenmotsu manifolds satisfying special types of nullity conditions depending on two smooth functions $\kappa,\mu$. When either $\kappa<-1$ and $\mu=0$ or $h=0$, such conditions coincide with the…

Differential Geometry · Mathematics 2013-01-29 Vincenzo Saltarelli

In this article, we define the Chern-Robinson connection on the complexify tangent bundle of an almost Robinson manifold and we study the curvature associated to. Various Bianchi identities are obtained together with an application to…

Differential Geometry · Mathematics 2026-02-20 Robert Petit

We find the first three most general Minkowski or Hsiung-Minkowski identities relating the total mean curvatures $H_i$, of degrees $i=1,2,3$, of a closed hypersurface $N$ immersed in a given orientable Riemannian manifold $M$ endowed with…

Differential Geometry · Mathematics 2021-09-06 R. Albuquerque

In this short note we prove that a Kahler manifold with lower Ricci curvature bound and almost maximal volume is Gromov-Hausdorff close to the projective space with the Fubini-Study metric. This is done by combining the recent results of…

Differential Geometry · Mathematics 2020-10-22 Ved Datar , Harish Seshadri , Jian Song

We give a rigorous account and prove continuity properties for the correspondence between almost flat bundles on a triangularizable compact connected space and the quasi-representations of its fundamental group. For a discrete countable…

Operator Algebras · Mathematics 2015-03-23 José R. Carrión , Marius Dadarlat

We complete the classification of compact Hermitian manifolds admitting a flat Gauduchon connection. In particular, we establish a conjecture of Yang and Zheng, showing that apart from the cases of a flat Chern or Bismut connection, such…

Differential Geometry · Mathematics 2022-07-20 Ramiro A. Lafuente , James Stanfield

We examine the class of compact Hermitian manifolds with constant holomorphic sectional curvature. Such manifolds are conjectured to be K\"ahler (hence a complex space form) when the constant is non-zero and Chern flat (hence a quotient of…

Differential Geometry · Mathematics 2022-10-18 Wu Zhou , Fangyang Zheng

We survey some recent results and constructions of almost-K\"ahler manifolds whose curvature tensors have certain algebraic symmetries. This is an updated and corrected version of the (to be) published manuscript.

Differential Geometry · Mathematics 2007-05-23 Vestislav Apostolov , Tedi Draghici

The aim of the present paper is to provide an \emph{intrinsic} investigation of the properties of the most important geometric objects associated with the fundamental linear connections in Finsler geometry. We investigate intrinsically the…

Differential Geometry · Mathematics 2014-11-18 Nabil L. Youssef , S. H. Abed , A. Soleiman

In this paper we consider a manifold $(M,\nabla )$ with a symmetric linear connection $\nabla $ which induces on the cotangent bundle $T^*M$ of $M$ a semi-Riemannian metric $\overline g$ with a neutral signature. The metric $\overline g$ is…

Differential Geometry · Mathematics 2018-03-28 Cornelia-Livia Bejan , Galia Nakova