Results 41 to 50 of about 71,381 (220)

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

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   +1 more source

The Sub-Riemannian Limit of Curvatures for Curves and Surfaces and a Gauss-Bonnet Theorem in the Group of Rigid Motions of Minkowski Plane with General Left-Invariant Metric

open access: yesJournal of Function Spaces, 2021
The group of rigid motions of the Minkowski plane with a general left-invariant metric is denoted by E1,1,gλ1,λ2, where λ1≥λ2>0. It provides a natural 2-parametric deformation family of the Riemannian homogeneous manifold Sol3=E1,1,g1,1 which is the ...
Jianyun Guan, Haiming Liu
doaj   +1 more source

Integral Formulas for a Foliation with a Unit Normal Vector Field

open access: yesMathematics, 2021
In this article, we prove integral formulas for a Riemannian manifold equipped with a foliation F and a unit vector field N orthogonal to F, and generalize known integral formulas (due to Brito-Langevin-Rosenberg and Andrzejewski-Walczak) for foliations ...
Vladimir Rovenski
doaj   +1 more source

On Weyl’s type theorems and genericity of projective rigidity in sub-Riemannian geometry [PDF]

open access: yesGeometriae Dedicata, 2020
Weyl (Zur Infinitisimalgeometrie: Einordnung der projektiven und der konformen Auffasung, Nachrichten von der K. Gesellschaft der Wissenschaften zu Göttingen, Mathematisch-Physikalische Klasse, Göttinger Akademie der Wissenschaften, Göttingen, 1921 ...
F. Jean, S. Maslovskaya, I. Zelenko
semanticscholar   +2 more sources

On the geometry of sub-Riemannian manifolds equipped with a canonical quarter-symmetric connection

open access: yesДифференциальная геометрия многообразий фигур, 2023
In this article, a sub-Riemannian manifold of contact type is under­stood as a Riemannian manifold equipped with a regular distribution of codimension-one and by a unit structure vector field orthogonal to this distribution. This vector field is called a
S. V. Galaev
doaj   +1 more source

Anisotropically Weighted and Nonholonomically Constrained Evolutions on Manifolds

open access: yesEntropy, 2016
We present evolution equations for a family of paths that results from anisotropically weighting curve energies in non-linear statistics of manifold valued data. This situation arises when performing inference on data that have non-trivial covariance and
Stefan Sommer
doaj   +1 more source

Curvature-dimension inequalities on sub-Riemannian manifolds obtained from Riemannian foliations, Part I [PDF]

open access: yes, 2015
We give a generalized curvature-dimension inequality connecting the geometry of sub-Riemannian manifolds with the properties of its sub-Laplacian. This inequality is valid on a large class of sub-Riemannian manifolds obtained from Riemannian foliations ...
Grong, Erlend, Thalmaier, Anton
core   +5 more sources

On 4-dimensional Einsteinian manifolds with parallel null distribution [PDF]

open access: yesریاضی و جامعه, 2023
In this paper, we investigate the Einsteinian manifolds with parallel null distribution. For this purpose, we first obtain the equations, which are known as Einstein's equations, that lead to finding the mentioned manifolds and then, we reduce Einstein's
Mehdi Jafari
doaj   +1 more source

The regularity problem for geodesics of the control distance

open access: yesBruno Pini Mathematical Analysis Seminar, 2018
In this survey, we present some recent results on the problem about the regularity of length-minimizing curves in sub-Riemannian geometry. We also sketch the possible application of some ideas coming from Geometric Measure Theory.
Roberto Monti
doaj   +1 more source

The left-invariant contact metric structure on the Sol manifold

open access: yesУчёные записки Казанского университета: Серия Физико-математические науки, 2020
Among the known eight-dimensional Thurston geometries, there is a geometry of the Sol manifold – a Lie group consisting of real special matrices. For a left-invariant Riemannian metric on the Sol manifold, the left shift group is a maximal simple ...
V.I. Pan’zhenskii, A.O. Rastrepina
doaj   +1 more source

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