We give an up-to-date perspective with a general overview of the theory of causal properties, the derived causal structures, their classification and applications, and the definition and construction of causal boundaries and of causal symmetries, mostly for Lorentzian manifolds but also in more abstract settings.
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The Abstract Boundary singularity theorem was first proven by Ashley and Scott. It links the existence of incomplete causal geodesics in strongly causal, maximally extended spacetimes to the existence of Abstract Boundary essential singularities, i.e., non-removable singular boundary points. We give two generalizations…
New findings on lightconvex boundaries in Finslerian spacetimes.
Recently, the old notion of causal boundary for a spacetime V has been redefined in a consistent way. The computation of this boundary for a standard conformally stationary spacetime V = R x M, suggests a natural compactification associated to any Riemannian metric on M or, more generally, to any Fin…
We construct an example which shows that two isocausal spacetimes, in the sense introduced by García-Parrado and Senovilla, may have c-boundaries which are not equal (more precisely, not equivalent, as no bijection between the completions can preserve all the binary relations induced by causality). This example also su…
Minimal TIP and TIF found in compact spacetimes, impacting spacetime splitting.
The paper proves a conjecture about spacetimes and singularities.
We show that when a spacetime is globally hyperbolic with (possibly empty) smooth timelike boundary , a metrizable topology, the closed limit topology (CLT) introduced by F. Hausdorff himself in the 1950's in set theory, can be advantageously adopted on the Geroch-Kronheime…
The notion of a causal boundary for a spacetime has been a controversial topic during the last three decades. Moreover, recently the role of the boundary in the AdS/CFT correspondence for plane waves, have stimulated its redefinition with some possible alternatives. Our aim is threefold. First, to review the different …
It is shown that the space of null geodesics of a star-shaped causally simple subset of Minkowski space is contactomorphic to the canonical contact structure in the spherical cotangent bundle of . In the -dimensional case we prove a similar result for a large class of causally simple contractible subse…
A new method selects covariates for causal effect estimation without strong assumptions.
FairTrade uses variational inference to create fair predictions in causal models.
A new method reduces CI tests for causal structure learning.
Framework calculates positional influence in causal residual Transformers.
Extends expected value framework for cost-sensitive causal decision-making.
Markov boundary improves tabular prediction but not as expected.
This paper is the continuation of [8]. We essentially prove that the familly of strongly causal spacetimes defined in [8] associated to generic achronal subsets in Ein contains all the examples of BTZ multi black-holes. It provides new elements for the global description of these multi black-holes. We also prove that a…
Globally hyperbolic spacetimes with timelike boundary are the natural class of spacetimes where regular boundary conditions (eventually asymptotic, if is obtained by means of a conformal embedding) can be posed. represents the naked singularities and c…
Paper improves feature selection for predicting outcomes from observational data.
We study in details the long-time asymptotic behavior of a relativistic diffusion taking values in the unitary tangent bundle of a curved Lorentzian manifold, namely a spatially flat and fast expanding Robertson-Walker space-time. We prove in particular that the Poisson boundary of the diffusion can be identified with …
Establishes a version of Bartnik's conjecture for Lorentzian length spaces.
This paper completes globally hyperbolic conformally flat spacetimes, proving they are topological manifolds.
We consider the future causal boundary as a tool to find obstructions to conformal extensions, the latter being a slight generalization to conformal compactifications.
Ridge regularized linear models (RRLMs), such as ridge regression and the SVM, are a popular group of methods that are used in conjunction with coefficient hypothesis testing to discover explanatory variables with a significant multivariate association to a response. However, many investigators are reluctant to draw ca…
We prove that the topology, smooth structure, and metric of a compact Lorentzian manifold with boundary is uniquely determined by data at the boundary. The data consists of the lengths and directions of future-directed once-broken geodesics connecting points on the boundary, which are first timelike and then lightlike.…
Study Gromov hyperbolic domains in Minkowski space, proving equivalence to boundary properties.
Recently ({\em Class. Quant. Grav.} {\bf 20} 625-664) the concept of {\em causal mapping} between spacetimes --essentially equivalent in this context to the {\em chronological map} one in abstract chronological spaces--, and the related notion of {\em causal structure}, have been introduced as new tools to study causal…
Bayesian method identifies causal sets across populations without graph knowledge.
We give new definitions of null infinity and black hole in terms of causal boundaries, applicable to any strongly causal spacetime . These are meant to extend the standard ones given in terms of conformal boundaries, and use the new definitions to prove a classic result in black hole theory for this more general…
Wave equation map reveals manifold's structure.
Study on merging predictors in causal and anticausal directions using CMAXENT.
We study smooth {\sf traversing} vector fields on compact manifolds with boundary. A traversing admits a Lyapunov function such that . We show that the trajectory spaces of {\sf traversally generic} -flows are {\sf Whitney stratified spaces}, and thus admit tr…
Study open orbits in causal flag manifolds with applications in AQFT.
CDFM aims to unify causal discovery across diverse datasets.
Recently, a new viewpoint on the classical c-boundary in Mathematical Relativity has been developed, the relations of this boundary with the conformal one and other classical boundaries have been analyzed, and its computation in some classes of spacetimes, as the standard stationary ones, has been carried out. In the p…
The paper is concerned with regularity properties of boundaries of causal pasts of points in a 3+1-dimensional Einstein-vacuum spacetime. In a Lorentzian manifold such boundaries play crucial role in propagation of linear and nonlinear waves. We prove a uniform lower bound on the radius of injectivity of these null bou…
Study subgroups preserving proper domains in flag manifolds.
Defines timelike ideal boundary for non-positively curved Lorentzian spaces.
New fairness criteria for algorithmic recourse actions that consider causal relationships.
New concept of Lorentzian-Euclidean black holes and metric transitions explored.
We study the causality relation in the 3-dimensional anti-de Sitter space AdS and its conformal boundary Ein. To any closed achronal subset in we associate the invisible domain from in AdS. We show that if is a torsion-free discrete group of isometries of AdS preserving and is non-elem…
Proposes a new model for online anomaly detection in multivariate time series.
Proposes a new method for algorithmic recourse in confounded settings.
In this paper, we determine the Poisson boundary of the relativistic Brownian motion in two classes of Lorentzian manifolds, namely model manifolds of constant scalar curvature and Robertson--Walker space-times, the latter constituting a large family of curved manifolds. Our objective is two fold: on the one hand, to u…
Recourse explanations can become invalid if collective actions change statistical data.
In this paper, we parametrize the space of isometric immersions of the hyperbolic plane into the hyperbolic 3-space in terms of null-causal curves in the space of oriented geodesics. Moreover, we characterize "ideal cones" (i.e., cones whose vertices are on the ideal boundary) by behavior of their mean curvature.
By using Stationary-to-Randers correspondence (SRC), a characterization of light and time-convexity of the boundary of a region of a standard stationary (n+1)-spacetime is obtained, in terms of the convexity of the boundary of a domain in a Finsler n or (n+1)-space of Randers type. The latter convexity is analyzed in d…
Lightlike hypersurfaces in cone structures minimize time.