Results 41 to 50 of about 892 (193)
Sub-Lorentzian Geometry of Curves and Surfaces in a Lorentzian Lie Group
Advances in Mathematical Physics, 2022 We consider the sub-Lorentzian geometry of curves and surfaces in the Lie group E1,1. Firstly, as an application of Riemannian approximants scheme, we give the definition of Lorentzian approximants scheme for E1,1 which is a sequence of Lorentzian ...
Haiming Liu, Jianyun Guan
doaj +1 more source
Entropy, 2019 For the 250th birthday of Joseph Fourier, born in 1768 at Auxerre in France, this MDPI special issue will explore modern topics related to Fourier analysis and Fourier Heat Equation.
Frédéric Barbaresco +1 more
doaj +1 more source
On the Subelliptic Eikonal Equation
Bruno Pini Mathematical Analysis Seminar, 2017 On a bounded smooth domain, we consider the viscosity solution of the homogeneous Dirichlet problem for the eikonal equation associated with a system of Hörmander’s vector fields.
Paolo Albano
doaj +1 more source
How smooth is quantum complexity?
Journal of High Energy Physics, 2021 The “quantum complexity” of a unitary operator measures the difficulty of its construction from a set of elementary quantum gates. While the notion of quantum complexity was first introduced as a quantum generalization of the classical computational ...
Vir B. Bulchandani, S. L. Sondhi
doaj +1 more source
Liouville Integrability in a Four-Dimensional Model of the Visual Cortex
Journal of Imaging, 2021 We consider a natural extension of the Petitot–Citti–Sarti model of the primary visual cortex. In the extended model, the curvature of contours is taken into account.
Ivan Galyaev, Alexey Mashtakov
doaj +1 more source
Homogeneous geodesics in sub-Riemannian geometry
ESAIM: Control, Optimisation and Calculus of Variations, 2023 We study homogeneous geodesics of sub-Riemannian manifolds, i.e., normal geodesics that are orbits of one-parametric subgroups of isometries. We obtain a criterion for a geodesic to be homogeneous in terms of its initial momentum. We prove that any weakly commutative sub-Riemannian homogeneous space is geodesic orbit, that means all geodesics are ...
openaire +2 more sources
A proof of a trace formula by Richard Melrose
Advanced Nonlinear Studies, 2023 The goal of this article is to give a new proof of the wave trace formula proved by Richard Melrose in an impressive article. This trace formula is an extension of the Chazarain-Duistermaat-Guillemin trace formula (denoted as “CDG trace formula” in this ...
Colin de Verdière Yves
doaj +1 more source
Cortical-inspired image reconstruction via sub-Riemannian geometry and hypoelliptic diffusion
ESAIM: Proceedings and Surveys, 2018 In this paper we review several algorithms for image inpainting based on the hypoelliptic diffusion naturally associated with a mathematical model of the primary visual cortex. In particular, we present one algorithm that does not exploit the information
Boscain Ugo +4 more
doaj +1 more source
Frontiers in Human Neuroscience, 2021 Objective: Tangent Space Mapping (TSM) using the geometric structure of the covariance matrices is an effective method to recognize multiclass motor imagery (MI).
Fan Wu +11 more
doaj +1 more source
Shortest and straightest geodesics in sub-Riemannian geometry [PDF]
Journal of Geometry and Physics, 2020 There are many equivalent definitions of Riemannian geodesics. They are naturally generalised to sub-Riemannian manifold, but become non-equivalent. We give a review of different definitions of geodesics of a sub-Riemannian manifold and interrelation between them.
openaire +3 more sources