Results 21 to 30 of about 2,719,579 (161)

On some methods of construction of invariant normalizations of lightlike hypersurfaces [PDF]

, 1999
The authors study the geometry of lightlike hypersurfaces on pseudo-Riemannian manifolds $(M, g)$ of Lorentzian signature. Such hypersurfaces are of interest in general relativity since they can be models of different types of physical horizons.
Akivis, Maks A., Goldberg, Vladislav V.
core   +3 more sources

Noncommutative Gravity Solutions

, 2009
We consider noncommutative geometries obtained from a triangular Drinfeld twist and review the formulation of noncommutative gravity. A detailed study of the abelian twist geometry is presented, including the fundamental theorem of noncommutative ...
Aschieri, Aschieri, Aschieri, Aschieri, Aschieri, Aschieri, Aschieri, Cacciatori, Cacciatori, Chaichian, Chu, Conlon, Connes, Connes, Drinfeld, Drinfeld, Foertsch, Gayral, Gerstenhaber, Klammer, Kobayashi, Kulish, Kulish, Leonardo Castellani, Lizzi, Ogievetsky, Ohl, Paolo Aschieri, Reshetikhin, Sitarz, Varilly, Varilly   +31 more
core   +2 more sources

Foundations of Ghost Stability

Fortschritte der Physik, EarlyView.
Abstract The authors present a new method to analytically prove global stability in ghost‐ridden dynamical systems. The proposal encompasses all prior results and consequentially extends them. In particular, it is shown that stability can follow from a conserved quantity that is unbounded from below, contrary to expectation.
Verónica Errasti Díez, Jordi Gaset Rifà, Georgina Staudt   +2 more
wiley   +1 more source

Polar Coordinates for the 3/2 Stochastic Volatility Model

Mathematical Finance, EarlyView.
ABSTRACT The 3/2 stochastic volatility model is a continuous positive process s with a correlated infinitesimal variance process ν$\nu $. The exact definition is provided in the Introduction immediately below. By inspecting the geometry associated with this model, we discover an explicit smooth map ψ$ \psi $ from (R+)2$({\mathbb{R}}^+)^2 $ to the ...
Paul Nekoranik
wiley   +1 more source

Social Rationality and Human Reasoning: Logical Expressivism and the Flat Mind

Topics in Cognitive Science, EarlyView.
Abstract This paper attempts to reconcile the claims that the mind is both flat (Chater, 2018) and highly rational (Oaksford & Chater, 2020). According to the flat mind hypothesis, the mind is a mass of inconsistent and contradictory fragments of experience.
Mike Oaksford
wiley   +1 more source

On Noncommutative and semi-Riemannian Geometry

, 2002
We introduce the notion of a semi-Riemannian spectral triple which generalizes the notion of spectral triple and allows for a treatment of semi-Riemannian manifolds within a noncommutative setting.
Alexander Strohmaier, Baum, Bognar, Cipriani, Connes, Connes, Dixmier, Gracia-Bondia, Hawkins, Kalau, Kastler, Kopf, Landi, O’Neill, Parfionov, Reed, Taylor   +16 more
core   +3 more sources

Asymptotic behavior of Moncrief Lines in constant curvature space‐times

Bulletin of the London Mathematical Society, EarlyView.
Abstract We study the asymptotic behavior of Moncrief lines on 2+1$2+1$ maximal globally hyperbolic spatially compact space‐time M$M$ of nonnegative constant curvature. We show that when the unique geodesic lamination associated with M$M$ is either maximal uniquely ergodic or simplicial, the Moncrief line converges, as time goes to zero, to a unique ...
Mehdi Belraouti, Abderrahim Mesbah, Lamine Messaci   +2 more
wiley   +1 more source

Curvature-dimension inequalities and Li-Yau inequalities in sub-Riemannian spaces

, 2013
In this paper we present a survey of the joint program with Fabrice Baudoin originated with the paper \cite{BG1}, and continued with the works \cite{BG2}, \cite{BBG}, \cite{BG3} and \cite{BBGM}, joint with Baudoin, Michel Bonnefont and Isidro Munive ...
AA Grigor'yan, B Pini, C Fefferman, D Bakry, DS Jerison, DS Kusuoka Stroock, EB Fabes, F Baudoin, HD Cao, KT Sturm, KT Sturm, KT Sturm, L Hörmander, L Saloff-Coste, M Rumin, R Strichartz, ST Yau, STP Yau Li   +17 more
core   +1 more source

Equal area partitions of the sphere with diameter bounds, via optimal transport

Bulletin of the London Mathematical Society, EarlyView.
Abstract We prove existence of equal area partitions of the unit sphere via optimal transport methods, accompanied by diameter bounds written in terms of Monge–Kantorovich distances. This can be used to obtain bounds on the expectation of the maximum diameter of partition sets, when points are uniformly sampled from the sphere.
Jun Kitagawa, Asuka Takatsu
wiley   +1 more source

On Lagrangian submersions

, 2014
In this paper, we study Riemannian, anti-invariant Riemannian and Lagrangian submersions. We prove that the horizontal distribution of a Lagrangian submersion from a Kaehlerian manifold is integrable.
Taştan, Hakan Mete
core   +1 more source