Results 11 to 20 of about 33,123 (219)

Multi-Frequency Image Completion via a Biologically-Inspired Sub-Riemannian Model with Frequency and Phase [PDF]

open access: yesJournal of Imaging, 2021
We present a novel cortically-inspired image completion algorithm. It uses five-dimensional sub-Riemannian cortical geometry, modeling the orientation, spatial frequency and phase-selective behavior of the cells in the visual cortex.
Emre Baspinar
doaj   +2 more sources

Sub-Riemannian geometry and Lie groups. Part II. Curvature of metric spaces, coadjoint orbits and associated representations

open access: green, 2004
This paper is the third in a series dedicated to the fundamentals of sub-Riemannian geometry and its implications in Lie groups theory: "Sub-Riemannian geometry and Lie groups.
Marius Buliga
openalex   +5 more sources

On the role of abnormal minimizers in sub-riemannian geometry [PDF]

open access: bronzeAnnales de la faculté des sciences de Toulouse Mathématiques, 2001
Consider a sub-Riemannian geometry $(U,D,g)$ where $U$ is a neighborhood at 0 in $\R^n,$ $D$ is a rank-2 smooth $(C^\infty $ or $C^ )$ distribution and $g$ is a smooth metric on $D$. The objective of this article is to explain the role of abnormal minimizers in SR-geometry. It is based on the analysis of the Martinet SR-geometry.
Bernard Bonnard, Emmanuel Trélat
openalex   +6 more sources

Sub-semi-Riemannian geometry on $H$-type groups [PDF]

open access: green, 2010
We consider $H$(eisenberg)-type groups whose law of left translation gives rise to a bracket generating distribution of step 2. In the contrast with sub-Riemannian studies we furnish the horizontal distribution with a nondegenerate indefinite metric of ...
Anna Korolko
openalex   +4 more sources

Curvature and the equivalence problem in sub-Riemannian geometry

open access: greenArchivum Mathematicum, 2022
These notes give an introduction to the equivalence problem of sub-Riemannian manifolds. We first introduce preliminaries in terms of connections, frame bundles and sub-Riemannian geometry. Then we arrive to the main aim of these notes, which is to give the description of the canonical grading and connection existing on sub-Riemann manifolds with ...
Erlend Grong
openalex   +4 more sources

Comparison theorems for conjugate points in sub-Riemannian geometry [PDF]

open access: yesESAIM: Control, Optimisation and Calculus of Variations, 2016
We prove sectional and Ricci-type comparison theorems for the existence of conjugate points along sub-Riemannian geodesics. In order to do that, we regard sub-Riemannian structures as a special kind of variational problems. In this setting, we identify a
Barilari, Davide, Rizzi, Luca
core   +10 more sources

Connections and Curvature in sub-Riemannian geometry

open access: green, 2009
For a subRiemannian manifold and a given Riemannian extension of the metric, we define a canonical global connection. This connection coincides with both the Levi-Civita connection on Riemannian manifolds and the Tanaka-Webster connection on strictly pseudoconvex CR manifolds.
Robert K. Hladky
openalex   +4 more sources

An Inverse Problem from sub-Riemannian geometry [PDF]

open access: bronzePacific Journal of Mathematics, 2003
The geodesics for a sub-Riemannian metric on a three-dimensional contact manifold $M$ form a 1-parameter family of curves along each contact direction. However, a collection of such contact curves on $M$, locally equivalent to the solutions of a fourth-order ODE, are the geodesics of a sub-Riemannian metric only if a sequence of invariants vanish.
Thomas Ivey
openalex   +4 more sources

Sub-Riemannian Geometry of Curves and Surfaces in Roto-Translation Group Associated with Canonical Connection [PDF]

open access: goldMathematics
The aim of this paper is to obtain the sub-Riemannian properties of the roto-translation group RT. At the same time, we compute the sub-Riemannian limits of Gaussian curvature associated with two kinds of canonical connections for a C2-smooth surface in ...
Han Zhang, Haiming Liu
doaj   +2 more sources

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