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There are five unimodular simply connected three dimensional unimodular non abelian Lie groups: the nilpotent Lie group $\mathrm{Nil}$, the special unitary group $\mathrm{SU}(2)$, the universal covering group…

Differential Geometry · Mathematics 2019-03-14 Mohamed Boucetta , Abdelmounaim Chakkar

With a f-left-invariant Riemannian metric on a Lie group $G$, we mean a Riemannian metric which is conformally equivalent to a left-invariant Riemannian metric, with the conformal factor $f$. In this article, we study the geometry of such…

Differential Geometry · Mathematics 2024-03-05 Hamid Reza Salimi Moghaddam

In this work it is shown that a necessary condition for the completeness of the geodesics of left invariant pseudo-Riemannian metrics on Lie groups is also sufficient in the case of 3-dimensional unimodular Lie groups, and not sufficient…

Differential Geometry · Mathematics 2008-12-18 Shirley Bromberg , Alberto Medina

We study left-invariant Killing $k$-forms on simply connected $2$-step nilpotent Lie groups endowed with a left-invariant Riemannian metric. For $k=2,3$, we show that every left-invariant Killing $k$-form is a sum of Killing forms on the…

Differential Geometry · Mathematics 2021-06-15 Viviana del Barco , Andrei Moroianu

We consider the completeness problem for left-invariant Lorentzian metrics on 3-dimensional non-unimodular Lie groups, all of which have Lie algebra of the form $\mathbb{R} \ltimes_A \mathbb{R}^2$, where $A$ is a real $2 \times 2$ matrix…

Differential Geometry · Mathematics 2025-10-14 Salah Chaib , Ana Cristina Ferreira

We study left-invariant symmetric Killing 2-tensors on 2-step nilpotent Lie groups endowed with a left-invariant Riemannian metric, and construct genuine examples, which are not linear combinations of parallel tensors and symmetric products…

Differential Geometry · Mathematics 2021-06-15 Viviana del Barco , Andrei Moroianu

In this paper, we investigate left invariant Riemannian metrics on Lie groups with one and two-dimensional commutator subgroups. We explicitly provide the Levi-Civita connection, sectional curvature, and Ricci curvature, and we give…

Differential Geometry · Mathematics 2026-01-19 Hamid Reza Salimi Moghaddam

Symmetric connections that are compatible with semi-Riemannian metrics can be characterized using an existence result for an integral leaf of a (possibly non integrable) distribution. In this paper we give necessary and sufficient…

Differential Geometry · Mathematics 2007-05-23 Paolo Piccione , Daniel V. Tausk

This is a collection of notes on the properties of left-invariant metrics on the eight-dimensional compact Lie group SU(3). Among other topics we investigate the existence of invariant pseudo-Riemannian Einstein metrics on this manifold. We…

Differential Geometry · Mathematics 2021-07-27 Robert Coquereaux

$k$-symplectic manifolds are a convenient framework to study classical field theories and they are a generalization of polarized symplectic manifolds. This paper focus on the existence and the properties of left invariant $k$-symplectic…

Differential Geometry · Mathematics 2023-02-21 Ilham Ait Brik , Mohamed Boucetta

A cyclic Riemannian Lie group is a Lie group $G$ equipped with a left-invariant Riemannian metric $h$ that satisfies $\oint_{X,Y,Z}h([X,Y],Z)=0$ for any left-invariant vector fields $X,Y,Z$. The initial concept and exploration of these Lie…

Differential Geometry · Mathematics 2025-04-24 Fatima-Ezzahrae Abid , Said Benayadi , Mohamed Boucetta , Hamza El Ouali , Hicham Lebzioui

We determine the index of symmetry of 3-dimensional unimodular Lie groups with a left-invariant metric. In particular, we prove that every 3-dimensional unimodular Lie group admits a left-invariant metric with positive index of symmetry. We…

Differential Geometry · Mathematics 2016-07-12 Silvio Reggiani

A Lorentzian Lie group is a Lie group endowed with a left invariant Lorentzian metric. We study left-invariant Codazzi tensors on Lorentzian Lie groups. We obtain new results on left-invariant Lorentzian metrics with harmonic curvature and…

Differential Geometry · Mathematics 2024-02-27 Ilyes Aberaouze , Mohamed Boucetta

In this work we provide a complete characterization of left-invariant symmetric Killing tensors on almost abelian Lie groups endowed with a left-invariant Riemannian metric. We show in particular that all such tensors are decomposable, in…

Differential Geometry · Mathematics 2025-10-01 Renan Berto-Cuevas , Viviana del Barco , Andrei Moroianu

For each connected and simply connected three-dimensional non-unimodular Lie group, we classify the left invariant Lorentzian metrics up to automorphism, and study the extent to which curvature can be altered by a change of metric. Thereby…

Differential Geometry · Mathematics 2022-09-07 Ku Yong Ha , Jong Bum Lee

We call a metric $m$-quasi-Einstein if $Ric_X^m$ (a modification of the $m$-Bakry-Emery Ricci tensor in terms of a suitable vector field $X$) is a constant multiple of the metric tensor. It is a generalization of Einstein metrics which…

Differential Geometry · Mathematics 2015-07-01 Zhiqi Chen , Ke Liang , Fahuai Yi

We describe the full group of isometries of each left invariant Riemannian metric on the simply connected unimodular nilpotent or solvable $(R)$-type Lie groups of dimension four.

Differential Geometry · Mathematics 2024-12-03 Youssef Ayad , Said Fahlaoui

In this paper, we study Lorentzian left invariant Einstein metrics on nilpotent Lie groups. We show that if the center of such Lie groups is degenerate then they are Ricci-flat and their Lie algebras can be obtained by the double extension…

Differential Geometry · Mathematics 2019-10-30 Mohamed Boucetta , Oumaima Tibssirte

In this survey we review recent results on left-invariant conformal Killing p-forms on Lie groups endowed with a left-invariant metric. We also mention interesting open questions that could lead into future research.

Differential Geometry · Mathematics 2023-12-29 A. Herrera , M. Origlia

This paper presents a complete classification of left-invariant affine and projective vector fields on five-dimensional simply connected nilpotent Lie groups endowed with Riemannian metrics. Building on the classification of left-invariant…

Differential Geometry · Mathematics 2025-09-18 M. L. Foka , R. P. Nimpa , M. B. N. Djiadeu