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Some problems of the space-time causal structure are discussed using models with traversable wormholes. For this purpose the conditions of traversable wormhole matching with the exterior space-time are considered in detail and a mixed…

General Relativity and Quantum Cosmology · Physics 2011-04-15 M. Yu. Konstantinov

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 introduce a class of first order G-structures, each of which has an underlying almost conformally symplectic structure. There is one such structure for each real simple Lie algebra which is not of type $C_n$ and admits a contact grading.…

Differential Geometry · Mathematics 2018-07-02 Andreas Cap , Tomas Salac

In their paper on multivariable dynamics, Davidson and Katsoulis conjectured that two multivariable dynamical systems have isomorphic tensor algebras if and only if they are piecewise conjugate. We disprove the conjecture by constructing…

Operator Algebras · Mathematics 2025-05-08 Boris Bilich

Causal structure learning from observational data remains a non-trivial task due to various factors such as finite sampling, unobserved confounding factors, and measurement errors. Constraint-based and score-based methods tend to suffer…

Machine Learning · Computer Science 2022-11-09 Rezaur Rashid , Jawad Chowdhury , Gabriel Terejanu

We get new results (and rederive some know ones) on smooth surfaces in $\mathbb{R}^n$ by unifying several view points into a coherent general view. Namely, we show and use new relations of the evolute (caustic) with the curvature ellipse,…

Differential Geometry · Mathematics 2025-09-09 Ricardo Uribe-Vargas

Let E be the restriction of the null-correlation bundle on $\mathbb{P}^{3}$ to a hyperplane. In this article, we show that the projective bundle $\mathbb{P}(E)$ is isomorphic to a blow-up of a non-singular quadric in $\mathbb{P}^{4}$ along…

Algebraic Geometry · Mathematics 2023-12-15 Shivam Vats

We consider causal 3-dimensional triangulations with the topology of $S^2\times [0,1]$ or $D^2\times [0,1]$ where $S^2$ and $D^2$ are the two-dimensional sphere and disc, respectively. These triangulations consist of slices and we show that…

Mathematical Physics · Physics 2021-01-29 Bergfinnur Durhuus , Thordur Jonsson

A hypersymplectic structure on a 4-manifold is a triple of symplectic forms for which any non-zero linear combination is again symplectic. In 2006, Donaldson conjectured that on a compact 4-manifold any hypersymplectic structure can be…

Symplectic Geometry · Mathematics 2025-08-14 Joel Fine , Weiyong He , Chengjian Yao

In this dissertation we develop a new formal graphical framework for causal reasoning. Starting with a review of monoidal categories and their associated graphical languages, we then revisit probability theory from a categorical perspective…

Probability · Mathematics 2013-01-29 Brendan Fong

In a general and non metrical framework, we introduce the class of co-CR quaternionic manifolds, which contains the class of quaternionic manifolds, whilst in dimension three it particularizes to give the Einstein-Weyl spaces. We show that…

Differential Geometry · Mathematics 2011-06-28 Stefano Marchiafava , Radu Pantilie

We describe topologically the discriminant locus of a smooth cubic surface in the complex projective space ${\mathbb{CP}}^3$ that contains 5 fibres of the projection ${\mathbb{CP}}^3 \longrightarrow S^4$.

Differential Geometry · Mathematics 2014-06-09 John Armstrong , Simon Salamon

Can the direction of time and the causal structure of space-time be inferred from operational principles? Causal models and tensor networks offer complementary perspectives: the former encodes cause-effect relations via directed graphs,…

Quantum Physics · Physics 2026-03-16 Carla Ferradini , Giulia Mazzola , V. Vilasini

Let S be the variety of irreducible sextics with six cusps as singularities. Let W be one of irreducible components of W. Denoting by M_4 the space of moduli of smooth curves of genus 4, the moduli map of W is the rational map from W to M_4…

Algebraic Geometry · Mathematics 2007-05-23 Concettina Galati

Graphical models can represent a multivariate distribution in a convenient and accessible form as a graph. Causal models can be viewed as a special class of graphical models that not only represent the distribution of the observed system…

Methodology · Statistics 2017-06-29 Christina Heinze-Deml , Marloes H. Maathuis , Nicolai Meinshausen

This article is part of an ongoing project aiming at the connections between causal structures on homogeneous spaces, Algebraic Quantum Field Theory (AQFT), modular theory of operator algebras and unitary representations of Lie groups. In…

Mathematical Physics · Physics 2022-10-28 Karl-Hermann Neeb , Gestur Olafsson

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

We investigate the causal relations in the space of states of almost commutative Lorentzian geometries. We fully describe the causal structure of a simple model based on the algebra $\mathcal{S}(\mathbb{R}^{1,1}) \otimes M_2(\mathbb{C})$,…

Mathematical Physics · Physics 2014-01-29 Nicolas Franco , Michał Eckstein

A piecewise constant curvature manifold is a triangulated manifold that is assigned a geometry by specifying lengths of edges and stipulating that for a chosen background geometry (Euclidean, hyperbolic, or spherical), each simplex has an…

Geometric Topology · Mathematics 2014-07-29 David Glickenstein , Joseph Thomas

In this paper, we show that the projection of a dualistic structure defined on a twisted product manifold induces dualistic structures on the base and the fiber manifolds, and conversely. Then under some conditions on the Ricci curvature…

Differential Geometry · Mathematics 2024-10-10 Abdoul Salam Diallo , Leonard Todjihounde
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