arXiv 1801.083062018-01-25math.DG

Affine surfaces which are Kähler, para-Kähler, or nilpotent Kähler

E. Calviño-Louzao, E. García-Río, P. Gilkey, I. Gutiérrez-Rodríguez, R. Vázquez-Lorenzo

英文摘要：

Motivated by the construction of Bach flat neutral signature Riemannian extensions, we study the space of parallel trace free tensors of type $(1,1)$ on an affine surface. It is shown that the existence of such a parallel tensor field is characterized by the recurrence of the symmetric part of the Ricci tensor.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

阅读原文

阅读 PDF ↗

arXiv 页面 ↗HTML 原文 ↗

本文内容

英文摘要相关论文

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

继续探索

相关论文

Conformal Einstein soliton within the framework of para-K$ä$hler manifold

The object of the present paper is to study some properties of para-K$ä$hler manifold whose metric is conformal Einstein soliton. We have studied some certain curvature properties of para-K$ä$hler manifold admitting conformal Einstein soliton.

2020-05-12math.DG

Left-invariant almost para-Kähler structures on six-dimensional nilpotent Lie groups

In this paper, we consider left-invariant para-complex structures on six-dimensional nilpotent Lie groups. A complete list of six-dimensional nilpotent Lie groups that admit para-Kähler structures is obtained, explicit expressions for para-complex structures are found, and curvature properties of associated para-Kähler metrics are investigated. It is shown that paracomplex structures are nilpotent and the corresponding para-Kähler metrics are Ricci-flat.

2022-08-14math.DG

Higher-dimensional Osserman metrics with non-nilpotent Jacobi operators

We exhibit Osserman metrics with non-nilpotent Jacobi operators and with non-trivial Jordan normal form in neutral signature (n,n) for any n which is at least 3. These examples admit a natural almost para-Hermitian structure and are semi para-complex Osserman with non-trivial Jordan normal form as well; they neither satisfy the third Gray identity nor are they integrable.

2010-07-15math.DG

Left-invariant almost para-complex structures on six-dimensional nilpotent Lie groups

There are five six-dimensional nilpotent Lie groups G, which do not admit neither symplectic, nor complex structures and, therefore, can be neither almost pseudo-Kahler, nor almost Hermitian. In this work, these Lie groups are being studied. The aim of the paper is to define new left-invariant geometric structures on the Lie groups under consideration that compensate, in some sense, the absence of symplectic and complex structures. New examples of multiparametric families of metrics of signature (3,3) and almost para-complex pseudo-Riemannian half-flat structures on six-dimensional nilmanifold…

2020-01-09math.DG

On parallel and symmetric 2-tensorfields on cones over pseudo-Riemannian manifolds

In this article, we study complete pseudo-Riemannian manifolds whose cone admits a parallel symmetric 2-tensorfield. The situation splits in three cases: nilpotent, decomposable or complex Riemannian. In the complex Riemannian and decomposable cases we provide a classification. In the nilpotent case, we are able to describe completely only a dense open subset of the manifold. To conclude, we give examples with non-constant curvature in the nilpotent case.

2010-11-08math.DG

Canonical pseudo-Kähler structures on six-dimensional nilpotent Lie groups

In this paper we consider left-invariant pseudo-Kähler structures on six-dimensional nilpotent Lie algebras. The explicit expressions of the canonical complex structures are calculated, and the curvature properties of the associated pseudo-Kähler metrics are investigated. It is proved that the associated pseudo-Kähler metric is Ricci-flat, that the curvature tensor has zero pseudo-Riemannian norm, and that the curvature tensor has some non-zero components that depend only on two or, at most, three parameters. The pseudo-Kähler structures obtained give basic models of pseudo-Kähler six-dimensio…

2013-11-14math.DG

更多相关论文收起更多论文

关于六维幂零非辛李群上的左不变半凯勒结构

On left-invariant semi-Kähler structures on six-dimensional nilpotent nonsymplectic Lie groups

本文针对三类六维幂零非辛李群，定义并研究了其上的左不变半凯勒结构与近仿半凯勒结构及其几何性质。

2024-09-04math.DG

Cohomogeneity-Three HyperKähler Metrics on Nilpotent Orbits

Let O be a nilpotent orbit in g^C where G is a compact, simple group and g=Lie(G). It is known that O carries a unique G-invariant hyperKähler metric admitting a hyperKähler potential compatible with the Kirillov-Kostant-Souriau symplectic form. In this work, the hyperKähler potential is explicitly calculated when O is of cohomogeneity three under the action of G. It is found that such a structure lies on a one-parameter family of hyperKähler metrics with G-invariant Kähler potentials if and only if g is sp(3), su(6), so(7), so(12) or e_7 and otherwise is the unique G-invariant hyperKähler met…

2004-06-01math.DG

定向中性向量丛的幂零结构

Nilpotent structures of oriented neutral vector bundles

本文针对秩 $4n$ 的定向中性向量丛，定义与中性超 Kähler 结构相关的 $H$-幂零结构，并证明其存在等价于由 $h$、$\ abla$、$I$、$J_1$、$J_2$ 构成中性超 Kähler 结构。

2024-12-04math.DG

2步幂零黎曼李群上的共形Killing形式

Conformal Killing forms on $2$-step nilpotent Riemannian Lie groups

该研究针对单连通2步幂零黎曼李群的左不变共形Killing 2、3-形式展开，证明中心维数≥4时这类形式均为Killing形式，还刻画了中心维数≤3时存在非上闭形式的所有群及其形式空间。

2021-01-21math.DG

Quasi-Kähler Chern-flat manifolds and complex 2-step nilpotent Lie algebras

The study of quasi-Kähler Chern-flat almost Hermitian manifolds is strictly related to the study of anti-bi-invariant almost complex Lie algebras. In the present paper we show that quasi-Kähler Chern-flat almost Hermitian structures on compact manifolds are in correspondence to complex parallelisable Hermitian structures satisfying the second Gray identity. From an algebraic point of view this correspondence reads as a natural correspondence between anti-bi-invariant almost complex structures on Lie algebras to bi-invariant complex structures. Some natural algebraic problems are approached and…

2011-01-10math.DG

Diagram involutions and homogeneous Ricci-flat metrics

We introduce a combinatorial method to construct indefinite Ricci-flat metrics on nice nilpotent Lie groups. We prove that every nilpotent Lie group of dimension $\leq6$, every nice nilpotent Lie group of dimension $\leq7$ and every two-step nilpotent Lie group attached to a graph admits such a metric. We construct infinite families of Ricci-flat nilmanifolds associated to parabolic nilradicals in the simple Lie groups ${\rm SL}(n)$, ${\rm SO}(p,q)$, ${\rm Sp}(n,\mathbb R)$. Most of these metrics are shown not to be flat.

2020-06-02math.DG

幂零希格斯丛与平坦联络族

Nilpotent Higgs bundles and families of flat connections

本文研究首项为幂零希格斯场的平坦联络族，证明其单值性与首项为正则希格斯丛的族相同，并由此得到和乐迹关于参数有理幂的渐近指数性质。

2022-07-19math.AGmath.DG