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An embedding is a mapping from a set of nodes of a network into a real vector space. Embeddings can have various aims like capturing the underlying graph topology and structure, node-to-node relationship, or other relevant information about…

Machine Learning · Computer Science 2023-06-21 Ashkan Dehghan , Kinga Siuta , Agata Skorupka , Andrei Betlen , David Miller , Bogumil Kaminski , Pawel Pralat

Statistical analysis of a graph often starts with embedding, the process of representing its nodes as points in space. How to choose the embedding dimension is a nuanced decision in practice, but in theory a notion of true dimension is…

Machine Learning · Statistics 2021-01-06 Patrick Rubin-Delanchy

Planar Embedding is a drawing of a graph on the plane such that the edges do not intersect each other except at the vertices. We know that testing the planarity of a graph and computing its embedding (if it exists), can efficiently be…

Data Structures and Algorithms · Computer Science 2023-07-19 Samir Datta , Asif Khan , Anish Mukherjee

We study Killing horizons and their neighbourhoods in the Kerr-NUT-(anti-)de Sitter and the accelerated Kerr-NUT-(anti-)de Sitter spacetimes. The geometries of the horizons have an irremovable singularity at one of the poles, unless the…

General Relativity and Quantum Cosmology · Physics 2020-10-28 Jerzy Lewandowski , Maciej Ossowski

Starting from the equations of motion in a 1 + 1 static, diagonal, Lorentzian spacetime, such as the Schwarzschild radial line element, I find another metric, but with Euclidean signature, which produces the same geodesics x(t). This…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Rickard Jonsson

Ordinal embedding aims at finding a low dimensional representation of objects from a set of constraints of the form "item $j$ is closer to item $i$ than item $k$". Typically, each object is mapped onto a point vector in a low dimensional…

Machine Learning · Computer Science 2021-05-26 Aïssatou Diallo , Johannes Fürnkranz

Previous studies on spacetime index of refraction are mostly restricted to the static spacetimes. In this study we fill this gap by introducing the refractive index for full stationary spacetimes, employing three different approaches. These…

General Relativity and Quantum Cosmology · Physics 2025-07-10 F. Masghatian , M. Esfandiar , M. Nouri-Zonoz

This paper aims at presenting a few models of quantum dynamics whose description involves the analysis of random unitary matrices for which dynamical localization has been proven to hold. Some models come from physical approximations…

Mathematical Physics · Physics 2011-05-03 Alain Joye

In this paper, conformal motions are studied in plane symmetric static spacetimes. The general solution of conformal Killing equations and the general form of the conformal Killing vector for these spacetimes are presented. All…

General Relativity and Quantum Cosmology · Physics 2009-11-13 K. Saifullah , Shair-e-Yazdan

Physically admissible choice of the "essential" coordinates identified with components of the metric tensor and co-moving frame of reference reduced to the formulation of the stationary axisymmetric GR problem. Such nontraditional approach…

General Relativity and Quantum Cosmology · Physics 2009-09-25 G. H. Haroutyunian

Implicit Neural Spatial Representation (INSR) has emerged as an effective representation of spatially-dependent vector fields. This work explores solving time-dependent PDEs with INSR. Classical PDE solvers introduce both temporal and…

Machine Learning · Computer Science 2023-06-01 Honglin Chen , Rundi Wu , Eitan Grinspun , Changxi Zheng , Peter Yichen Chen

We show that the only locally integrable stationary solutions to the integrated Kuramoto-Sivashinsky equation in $R$ and $R^2$ are the trivial constant solutions. We extend our technique and prove similar results to other nonlinear elliptic…

Analysis of PDEs · Mathematics 2007-05-23 Yanping Cao , Edriss S. Titi

The integrability in quadratures of normality equation for spatially homogeneous dynamical systems in two-dimensional space is shown. The classical symmetries of this equation are calculated and the corresponding self-similar solutions are…

patt-sol · Physics 2008-02-03 A. Yu. Boldin

Consider the energy $E_\alpha[\Sigma]=\int_\Sigma |p|^\alpha\, d\Sigma$, where $\Sigma$ is a surface in Euclidean space $\r^3$ and $\alpha\in\r$. We prove that planes and spheres are the only stationary surfaces for $E_\alpha$ with constant…

Differential Geometry · Mathematics 2025-07-18 Rafael López

A generic method for combinatorial constructions of intrinsic geometrical spaces is presented. It is based on the well known inverse sequences of finite graphs that determine (in the limit) topological spaces. If a pattern of the…

Computational Geometry · Computer Science 2020-10-09 Stanislaw Ambroszkiewicz

We study embeddings of continuous dynamical systems in larger dimensions via projector operators. We call this technique PEDS, projective embedding of dynamical systems, as the stable fixed point of the dynamics are recovered via projection…

Dynamical Systems · Mathematics 2023-10-19 Francesco Caravelli , Fabio L. Traversa , Michele Bonnin , Fabrizio Bonani

Embedding theorems have continued to be a topic of interest in the general theory of relativity since these help connect the classical theory to higher-dimensional manifolds. This paper deals with spacetimes of embedding class one, i.e.,…

General Relativity and Quantum Cosmology · Physics 2018-05-29 Peter K. F. Kuhfittig

We present a useful method for the construction of cosmological models by solving the differential equations arising from calculating the kinematical invariants (shear, rotation, expansion and acceleration) of an observer field in proper…

General Relativity and Quantum Cosmology · Physics 2008-01-24 M. Plaue , M. Scherfner , L. A. M. de Sousa

A trajectory isomorphism between the two Newtonian fixed center problem in the sphere and two associated planar two fixed center problems is constructed by performing two simultaneous gnomonic projections in $S^2$. This isomorphism converts…

Mathematical Physics · Physics 2017-10-03 M. A. Gonzalez Leon , J. Mateos Guilarte , M. de la Torre Mayado

Specific examples of the generalized Raychaudhuri Equations for the evolution of deformations along families of $D$ dimensional surfaces embedded in a background $N$ dimensional spacetime are discussed. These include string worldsheets…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Sayan Kar