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We prove the existence and uniqueness of graphs with prescribed mean curvature function in a large class of Riemannian manifolds which comprises spaces endowed with a conformal Killing vector field.

Differential Geometry · Mathematics 2009-04-08 Marcos Dajczer , Jorge H. S. de Lira

The theory of harmonic vector fields on Riemannian manifolds is generalised to pseudo-Riemannian manifolds. Harmonic conformal gradient fields on pseudo-Euclidean hyperquadrics are classified up to congruence, as are harmonic Killing fields…

Differential Geometry · Mathematics 2016-10-31 R. M. Friswell , C. M. Wood

By studying spaces of flow graphs in a closed oriented manifold, we construct operations on its cohomology, parametrized by the homology of the moduli spaces of compact Riemann surfaces with boundary marked points. We show that the…

Geometric Topology · Mathematics 2013-05-03 Viktor Fromm

We establish normal forms for conformal vector fields on pseudo-Riemannian manifolds in the neighborhood of a singularity. For real-analytic Lorentzian manifolds, we show that the vector field is analytically linearizable or the manifold is…

Differential Geometry · Mathematics 2012-09-19 Charles Frances , Karin Melnick

In this paper we introduce and study a geometric heat flow to find Killing vector fields on closed Riemannian manifolds with positive sectional curvature. We study its various properties, prove the global existence of the solution of this…

Differential Geometry · Mathematics 2014-06-03 Yi Li , Kefeng Liu

This paper investigates timelike conformal vector fields on closed Lorentzian $3$-manifolds and shows that, although these fields form a broader class than Killing fields, their behavior in dimension three is nonetheless remarkably rigid.…

Differential Geometry · Mathematics 2026-01-06 Emmanuel Gnandi , Fortuné Massamba

Let X be a divergence-free vector field defined on a closed, connected Riemannian manifold. In this paper, we show the equivalence between the following conditions: 1. X is in the C1-interior of the set of expansive divergence-free vector…

Dynamical Systems · Mathematics 2010-11-17 Célia Ferreira

In this paper we continue the study of bi-conformal vector fields started in {\em Class. Quantum Grav.} {\bf 21} 2153-2177. These are vector fields defined on a pseudo-Riemannian manifold by the differential conditions $\lie P_{ab}=\phi…

Differential Geometry · Mathematics 2016-08-16 Alfonso García-Parrado Gómez-Lobo

In this paper, using connections between Clifford-Wolf isometries and Killing vector fields of constant length on a given Riemannian manifold, we classify simply connected Clifford-Wolf homogeneous Riemannian manifolds. We also get the…

Differential Geometry · Mathematics 2008-04-01 V. N. Berestovskii , Yu. G. Nikonorov

We introduce a complete obstruction to the existence of nonvanishing vector fields on a closed orbifold $Q$. Motivated by the inertia orbifold, the space of multi-sectors, and the generalized orbifold Euler characteristics, we construct for…

Differential Geometry · Mathematics 2009-12-09 Carla Farsi , Christopher Seaton

A differential form defined on a Riemannian manifold is said to harmonic if it is closed and co-closed. Harmonic differential forms are a natural multi-dimensional extension of the concept of analytic function of complex variable. In this…

Functional Analysis · Mathematics 2007-05-23 René Dáger , Arturo Presa

We prove the existence of solutions to the conformal Einstein-scalar constraint system of equations for closed compact Riemannian manifolds in the positive case. Our results apply to the vacuum case with positive cosmological constant and…

Analysis of PDEs · Mathematics 2015-06-12 Bruno Premoselli

In this paper, we characterize conformal vector fields of any (regular or singular) $(\alpha,\beta)$-space with some PDEs. Further, we show some properties of conformal vector fields of a class of singular $(\alpha,\beta)$-spaces satisfying…

Differential Geometry · Mathematics 2018-02-07 Guojun Yang

Let $(M^n,g)$ be an $n$-dimensional compact connected Riemannian manifold with smooth boundary. We show that the presence of a nontrivial conformal gradient vector field on $M$, with an appropriate control on the Ricci curvature makes $M$…

Differential Geometry · Mathematics 2021-10-26 Israel Evangelista , Emanuel Viana

Let $(M^n,g)$ be an $n$-dimensional compact connected Riemannian manifold with boundary. In this article, we study the effects of the presence of a nontrivial conformal vector field on $(M^n,g)$. We used the wekk-known de-Rham Laplace…

Differential Geometry · Mathematics 2021-12-22 Antônio Freitas , Israel Evangelista , Emanuel Viana

We introduce an appropriate formalism in order to study conformal Killing (symmetric) tensors on Riemannian manifolds. We reprove in a simple way some known results in the field and obtain several new results, like the classification of…

Differential Geometry · Mathematics 2017-01-20 Konstantin Heil , Andrei Moroianu , Uwe Semmelmann

We characterize the exact lumpability of smooth vector fields on smooth manifolds. We derive necessary and sufficient conditions for lumpability and express them from four different perspectives, thus simplifying and generalizing various…

Differential Geometry · Mathematics 2016-07-07 Leonhard Horstmeyer , Fatihcan M. Atay

Direct integration technique is used to study the proper conformal vector fields in non conformally flat Bianchi type-1 space-times. Using the above mentioned technique we have shown that a very special class of the above space-time admits…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ghulam Shabbir , Shaukat Iqbal

In this paper, we study complete Vacuum Static Spaces. A complete classification of 3-dimensional complete Vacuum Static Spaces with non-negative scalar curvature and constant squared norm of Ricci curvature tensor is given by making use of…

Differential Geometry · Mathematics 2023-07-13 Qing-Ming Cheng , Guoxin Wei

A new class of conformal field theories is presented, where the background gravitational field is conformally flat. Conformally flat (CF) spacetimes enjoy conformal properties quite similar to the ones of flat spacetime. The conformal…

High Energy Physics - Theory · Physics 2020-07-01 Enrique Alvarez , Raquel Santos-Garcia