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We are studying the harmonic and twistor equation on Lorentzian surfaces, that is a two dimensional orientable manifold with a metric of signature $(1,1)$. We will investigate the properties of the solutions of these equations and try to…

Differential Geometry · Mathematics 2010-12-30 Frederik Witt

We present conformal structures in signature (3,2) for which the holonomy of the Fefferman-Graham ambient metric is equal to the non-compact exceptional Lie group G_{2(2)}. We write down the resulting 8-parameter family of G_{2(2)}-metrics…

Differential Geometry · Mathematics 2012-08-14 Thomas Leistner , Pawel Nurowski

A review of some facts concerning classical spacetime geometry is presented together with a description of the most elementary aspects of the two-component spinor formalisms of Infeld and van der Waerden. Special attention is concentrated…

Mathematical Physics · Physics 2016-12-22 Jorge G. Cardoso

The notions of the interior and truncated connections of a nonholonomic manifold are introduced. A class of extended truncated connections is distinguished. For the case of a contact space with a Finsler metric, it is shown that there…

Differential Geometry · Mathematics 2011-03-23 Sergey V. Galaev

We obtain a correspondence between irreducible real parallel spinors on pseudo-Riemannian manifolds $(M,g)$ of signature $(4,3)$ and solutions of an associated differential system for three-forms that satisfy a homogeneous algebraic…

Differential Geometry · Mathematics 2025-03-26 Alejandro Gil-García , C. S. Shahbazi

Given any two Einstein (pseudo-)metrics, with scalar curvatures suitably related, we give an explicit construction of a Poincar\'e-Einstein (pseudo-)metric with conformal infinity the conformal class of the product of the initial metrics.…

Differential Geometry · Mathematics 2009-11-16 A. Rod Gover , Felipe Leitner

In this manuscript, a conformally invariant theory of gravitation in the context of metric measure space is studied. The proposed action is invariant under both diffeomorphism and conformal transformations. Using the variational method, a…

General Relativity and Quantum Cosmology · Physics 2015-10-06 Nafiseh Rahmanpour , Hossein Shojaie

We study the geometric properties of a $(2m+1)$-dimensional complex manifold $\mathcal{M}$ admitting a holomorphic reduction of the frame bundle to the structure group $P \subset \mathrm{Spin}(2m+1,\mathbb{C})$, the stabiliser of the line…

Differential Geometry · Mathematics 2018-07-16 Arman Taghavi-Chabert

The aim of the present paper is to provide an intrinsic investigation of projective changes in Finlser geometry, following the pullback formalism. Various known local results are generalized and other new intrinsic results are obtained.…

Differential Geometry · Mathematics 2013-04-29 Nabil L. Youssef , S. H. Abed , A. Soleiman

The primary aim of this thesis is to investigate metrics which are induced by a differential form and arise as a critical point of Hitchin's variational principle. Firstly, we investigate metrics associated with the structure group PSU(3)…

Differential Geometry · Mathematics 2007-05-23 Frederik Witt

A conformal description of Poincare-Einstein manifolds is developed: these structures are seen to be a special case of a natural weakening of the Einstein condition termed an almost Einstein structure. This is used for two purposes: to shed…

Differential Geometry · Mathematics 2008-04-25 A. Rod Gover

We introduce a generalisation of Fefferman's conformal circle bundle over a contact Cauchy-Riemann three-manifold. These can be viewed as exact `perturbations' of Fefferman's structure by a semi-basic one-form, which encodes additional data…

Differential Geometry · Mathematics 2025-12-30 Arman Taghavi-Chabert

The curvature properties of Robinson-Trautman metric have been investigated. It is shown that Robinson-Trautman metric admits several kinds of pseudosymmetric type structures such as Weyl pseudosymmetric, Ricci pseudosymmetric,…

Differential Geometry · Mathematics 2017-01-24 Absos Ali Shaikh , Musavvir Ali , Zafar Ahsan

We construct the explicit form of three almost complex structures that a Riemannian manifold with self-dual curvature admits and show that their Nijenhuis tensors vanish so that they are integrable. This proves that gravitational instantons…

General Relativity and Quantum Cosmology · Physics 2015-06-25 A. N. Aliev , Y. Nutku

Weyl's conformal theory of gravity is an extension of Einstein's theory of general relativity which associates metrics with 1-forms . In the case of locally integrable (closed non-exact) 1-forms the spacetime manifolds are no more simply…

General Relativity and Quantum Cosmology · Physics 2022-06-09 Michel Duneau

Smooth deformations of a Minkowski type metric in a four-dimensional space-time manifold are considered. Deformations of the basic spin-tensorial fields associated with this metric are calculated and their application to calculating the…

Differential Geometry · Mathematics 2007-09-11 Ruslan Sharipov

We show the existence of a modified Cliff(1,1) structure compatible with an Osserman 0-model of signature (2,2). We then apply this algebraic result to certain classes of pseudo-Riemannian manifolds of signature (2,2). We obtain a new…

Differential Geometry · Mathematics 2015-05-13 Novica Blazic , Peter Gilkey , Stana Nikcevic , Iva Stavrov

We consider the twistor description of conformal higher spin theories and give twistor space actions for the self-dual sector of theories with spin greater than two that produce the correct flat space-time spectrum. We identify a ghost-free…

High Energy Physics - Theory · Physics 2017-11-22 Philipp Haehnel , Tristan McLoughlin

It is shown that the variational derivative of the integral of Branson's Q-curvature is the ambient obstruction tensor of Fefferman-Graham. A classification of irreducible conformally invariant tensors modulo quadratic and higher degree…

Differential Geometry · Mathematics 2007-05-23 C. Robin Graham , Kengo Hirachi

This is the first of two companion papers in which a thorough study of the normal form and the first integrability conditions arising from {\em bi-conformal vector fields} is presented. These new symmetry transformations were introduced in…

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