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Related papers: Almost Kahler forms on rational 4-manifolds

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We study the quantization of a holomorphic two-form coupled to a Yang-Mills field on special manifolds in various dimensions, and we show that it yields twisted supersymmetric theories. The construction determines ATQFT's (Almost…

High Energy Physics - Theory · Physics 2015-06-26 Laurent Baulieu , Alessandro Tanzini

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

In this paper we present some approaches to classification of almost complex structures and to construction of local or formal pseudoholomorphic mapping from one almost complex manifold to another. The corresponding criteria are given in…

dg-ga · Mathematics 2008-02-03 Boris S. Kruglikov

Let $(M,J)$ be a $2n$-dimensional almost complex manifold and let $x\in M$. We define the notion of almost complex blow-up of $(M,J)$ at $x$. We prove the existence of almost complex blow-ups at $x$ under suitable assumptions on the almost…

Differential Geometry · Mathematics 2023-05-18 Richard Hind , Tommaso Sferruzza , Adriano Tomassini

We give the first examples of groups which admit a tame combing with linear radial tameness function with respect to any choice of finite presentation, but which are not minimally almost convex on a standard generating set. Namely, we…

Group Theory · Mathematics 2018-03-19 Sean Cleary , Susan Hermiller , Melanie Stein , Jennifer Taback

In this paper we look at the question of integrability, or not, of the two natural almost complex structures $J^{\pm}_\nabla$ defined on the twistor space $J(M,g)$ of an even-dimensional manifold $M$ with additional structures $g$ and…

Differential Geometry · Mathematics 2021-04-27 Michel Cahen , Simone Gutt , John Rawnsley

We apply Zhang's almost K\"ahler Nakai-Moishezon theorem and Li-Zhang's comparison of $J$-symplectic cones to establish a stability result for the symplectomorphism group of a rational $4$-manifold $M$ with Euler number up to $12$. As a…

Symplectic Geometry · Mathematics 2023-06-06 Silvia Anjos , Jun Li , Tian-Jun Li , Martin Pinsonnault

Let $(G,g)$ be a 4-dimensional Riemannian Lie group with a 2-dimensional left-invariant, conformal foliation $\F$ with minimal leaves. Let $J$ be an almost Hermitian structure on $G$ adapted to the foliation $\F$. We classify such…

Differential Geometry · Mathematics 2022-01-12 Emma Andersdotter Svensson , Sigmundur Gudmundsson

We study and classify almost complex totally geodesic submanifolds of the nearly Kaehler flag manifold $F_{1,2}(\mathbb C^3)$, and of its semi-Riemannian counterpart. We also develop a structural approach to the nearly Kaehler flag manifold…

Differential Geometry · Mathematics 2021-07-05 Kamil Cwilinski , Luc Vrancken

T.-J. Li and W. Zhang defined an almost complex structure $J$ on a manifold $X$ to be {\em \Cpf}, if the second de Rham cohomology group can be decomposed as a direct sum of the subgroups whose elements are cohomology classes admitting…

Symplectic Geometry · Mathematics 2012-11-13 Richard Hind , Costantino Medori , Adriano Tomassini

We show the existence and uniqueness of solutions to a generalized Monge-Amp\`{e}re equation on closed almost K\"ahler surfaces, where the equation depends only on the underlying almost K\"ahler structure. As an application, we prove…

Differential Geometry · Mathematics 2025-05-05 Ken Wang , Zuyi Zhang , Tao Zheng , Peng Zhu

Let $(M,J)$ be a complex manifold of complex dimension $n$. A $p$-K\"ahler structure on $(M,J)$ is a real, closed $(p,p)$-transverse form. In this paper, we address the conjecture of L. Alessandrini and G. Bassanelli on $(n-2)$-K\"ahler…

Differential Geometry · Mathematics 2025-06-17 Ettore Lo Giudice

We review the recent development of Hodge theory for almost complex manifolds. This includes the determination of whether the Hodge numbers defined by $\bar\partial$-Laplacian are almost complex, almost K\"ahler, or birational invariants in…

Differential Geometry · Mathematics 2022-03-18 Weiyi Zhang

We use a natural affine connection with nontrivial torsion on an arbitrary almost-Kaehler manifold which respects the almost-Kaehler structure to construct a Fedosov-type deformation quantization on this manifold.

Quantum Algebra · Mathematics 2007-05-23 Alexander V. Karabegov , Martin Schlichenmaier

The space $SL(2,\mathbb{R})\times SL(2,\mathbb{R})$ admits a natural homogeneous pseudo-Riemannian nearly Kaehler structure. We investigate almost complex surfaces in this space. In particular we obtain a complete classification of the…

Differential Geometry · Mathematics 2020-06-23 Elsa Ghandour , Luc Vrancken

We classify compact self-dual almost-K\"ahler four manifolds of positive type and zero type. In particular, using LeBrun's result, we show that any self-dual almost-K\"ahler metric on a manifold which is diffeomorphic to $\mathbb{CP}_{2}$…

Differential Geometry · Mathematics 2023-11-30 Inyoung Kim

For an almost contact metric manifold $N$, we find conditions for which either the total space of an $S^1$-bundle over $N$ or the Riemannian cone over $N$ admits a strong K\"ahler with torsion (SKT) structure. In this way we construct new…

Differential Geometry · Mathematics 2010-11-19 Marisa Fernandez , Anna Fino , Luis Ugarte , Raquel Villacampa

We discuss a conjecture of Donaldson on a version of Yau's Theorem for symplectic forms with compatible almost complex structures and survey some recent progress on this problem. We also speculate on some future possible directions, and use…

Differential Geometry · Mathematics 2011-07-06 Valentino Tosatti , Ben Weinkove

We introduce the notion of a $\theta$-almost twisted Poisson structure on manifolds, which involves incorporating a closed $1$-form $\theta$ into twisted Poisson structures under specific conditions. We provide a characterization of this…

Differential Geometry · Mathematics 2025-09-12 Nasser Saipele Nansidi , Bertuel Tangue Ndawa , Joseph Dongho

A compact symplectic manifold $(M, \omega)$ is said to satisfy the hard-Lefschetz condition if it is possible to develop an analogue of Hodge theory for $(M, \omega)$. This loosely means that there is a notion of harmonicity of differential…

Differential Geometry · Mathematics 2024-11-25 Adrián Andrada , Agustín Garrone