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A unifying framework for the study of causal relations is presented. The causal relations are regarded as subsets of M x M and the role of the corresponding antisymmetry conditions in the construction of the causal ladder is stressed. The…

General Relativity and Quantum Cosmology · Physics 2011-07-08 E. Minguzzi

The space of light rays $\mathcal{N}$ of a conformal Lorentz manifold $(M,\mathcal{C})$ is, under some topological conditions, a manifold whose basic elements are unparametrized null geodesics. This manifold $\mathcal{N}$, strongly inspired…

General Relativity and Quantum Cosmology · Physics 2022-06-29 A. Bautista , A. Ibort , J. Lafuente

We construct stationary flat three-dimensional Lorentzian manifolds with singularities that are obtained from Euclidean surfaces with cone singularities and closed one-forms on these surfaces. In the application to (2+1)-gravity, these…

Differential Geometry · Mathematics 2014-03-20 Thierry Barbot , Catherine Meusburger

In this review, we discuss approaches for learning causal structure from data, also called causal discovery. In particular, we focus on approaches for learning directed acyclic graphs (DAGs) and various generalizations which allow for some…

Methodology · Statistics 2022-12-20 Chandler Squires , Caroline Uhler

We show that a non-commutative structure arises naturally from perturbative quantum gravity in a de Sitter background metric. Our work builds on recent advances in the construction of observables in highly symmetric background spacetimes…

General Relativity and Quantum Cosmology · Physics 2023-10-10 Markus Fröb , William C. C. Lima , Albert Much , Kyriakos Papadopoulos

For each connected complex reductive group G, we find a family of new examples of complex quasi-Hamiltonian G-spaces with G-valued moment maps. These spaces arise naturally as moduli spaces of (suitably framed) meromorphic connections on…

Differential Geometry · Mathematics 2026-03-10 Philip Boalch

Using K-causal relation introduced by Sorkin and Woolgar [26], we gener- alize results of Garcia-Parrado and Senovilla [8, 9] on causal maps. We also introduce causality conditions with respect to K-causality which are analogous to those in…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Sujatha Janardhan , R. V. Saraykar

We consider examples of the $\mathbb H$-type groups with the natural horizontal distribution generated by the commutation relations of the group. In the contrast with the previous studies we furnish the horizontal distribution with the…

Differential Geometry · Mathematics 2008-09-26 Anna Korolko , Irina Markina

In this work we provide the full description of the upper levels of the classical causal ladder for spacetimes in the context of Lorenztian length spaces, thus establishing the hierarchy between them. We also show that global hyperbolicity,…

General Relativity and Quantum Cosmology · Physics 2020-10-16 L. Ake Hau , Armando J. Cabrera Pacheco , Didier A. Solis

The metric field of general relativity is almost fully determined by its causal structure. Yet, in spin-foam models for quantum gravity, the role played by the causal structure is still largely unexplored. The goal of this paper is to…

General Relativity and Quantum Cosmology · Physics 2026-04-28 Eugenio Bianchi , Pierre Martin-Dussaud

We investigate here the causal structure of spacetime in the vicinity of a spacetime singularity. The particle and energy emission from such ultra-dense regions forming in gravitational collapse of a massive matter cloud is governed by the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Pankaj S. Joshi

In general relativity, `causal structure' refers to the partial order on space-time points (or regions) that encodes time-like relationships. Recently, quantum information and quantum foundations saw the emergence of a `causality…

Quantum Physics · Physics 2017-08-16 Aleks Kissinger , Matty Hoban , Bob Coecke

We discuss contact invariant structures on the space of solutions of a third-order ordinary differential equation. Associated to any third-order differential equation modulo contact transformations, Chern introduced a degenerate conformal…

Differential Geometry · Mathematics 2010-01-05 Jonathan Holland , George Sparling

We investigate the extrinsic geometry of causal sets in $(1+1)$-dimensional Minkowski spacetime. The properties of boundaries in an embedding space can be used not only to measure observables, but also to supplement the discrete action in…

General Relativity and Quantum Cosmology · Physics 2018-06-27 William J. Cunningham

Prior work has shown that causal structure can be uniquely identified from observational data when these follow a structural equation model whose error terms have equal variances. We show that this fact is implied by an ordering among…

Methodology · Statistics 2021-05-25 Wenyu Chen , Mathias Drton , Y. Samuel Wang

Semi-Riemannian manifolds that satisfy (homogeneous) linear differential conditions of arbitrary order on the curvature are analyzed. They include, in particular, the spaces with (higher-order) recurrent curvature, (higher-order) symmetric…

Differential Geometry · Mathematics 2024-04-24 José M. M. Senovilla

The hypothesis that the causal properties of space-time, as well as other properties of physical systems like unitarity, charge conservation, etc., might be decided by the higher dimensional structure (in particular, higher-dimensional…

High Energy Physics - Phenomenology · Physics 2007-06-26 Israel Quiros

We consider principal fibre bundles with a given connection and construct almost complex structures on the total space if the adjoint bundle is isomorphic to the tangent bundle of the base. We derive the integrability condition. If the…

Differential Geometry · Mathematics 2017-02-15 Raphael Zentner

The original models of causal dynamical triangulations construct space-time by arranging a set of simplices in layers separated by a fixed time-like distance. The importance of the foliation structure in the 2+1 dimensional model is studied…

High Energy Physics - Theory · Physics 2009-11-11 Tomasz Konopka

A fundamental challenge of scientific research is inferring causal relations based on observed data. One commonly used approach involves utilizing structural causal models that postulate noisy functional relations among interacting…

Methodology · Statistics 2024-08-13 David Strieder , Mathias Drton