Results 91 to 100 of about 33,123 (219)

Generalized Force Method for Point‐To‐Point Ray Tracing in Anisotropic Ionosphere: Implementation and Applications to NeQuick2 and IGRF13 Models

Radio Science, Volume 60, Issue 3, March 2025.
Abstract The generalized force method, previously developed for an isotropic inhomogeneous ionosphere, exploits the knowledge about the character of the extrema of the phase distance—where high ionospheric rays correspond to minima and low rays to saddle points—to systematically find all relevant rays between fixed points, thereby enabling efficient ...
I. A. Nosikov, M. V. Klimenko, A. M. Padokhin, V. V. Nosikova, P. F. Bessarab   +4 more
wiley   +1 more source

Mabuchi Kähler solitons versus extremal Kähler metrics and beyond

Bulletin of the London Mathematical Society, Volume 57, Issue 3, Page 692-710, March 2025.
Abstract Using the Yau–Tian–Donaldson type correspondence for v$v$‐solitons established by Han–Li, we show that a smooth complex n$n$‐dimensional Fano variety admits a Mabuchi soliton provided it admits an extremal Kähler metric whose scalar curvature is strictly less than 2(n+1)$2(n+1)$.
Vestislav Apostolov, Abdellah Lahdili, Yasufumi Nitta   +2 more
wiley   +1 more source

Biflat F‐structures as differential bicomplexes and Gauss–Manin connections

Bulletin of the London Mathematical Society, Volume 57, Issue 3, Page 786-808, March 2025.
Abstract We show that a biflat F‐structure (∇,∘,e,∇∗,∗,E)$(\nabla,\circ,e,\nabla ^*,*,E)$ on a manifold M$M$ defines a differential bicomplex (d∇,dE∘∇∗)$(d_{\nabla },d_{E\circ \nabla ^*})$ on forms with value on the tangent sheaf of the manifold. Moreover, the sequence of vector fields defined recursively by d∇X(α+1)=dE∘∇∗X(α)$d_{\nabla }X_{(\alpha +1)}
Alessandro Arsie, Paolo Lorenzoni
wiley   +1 more source

The sphere and the cut locus at a tangency point in two-dimensional almost-Riemannian geometry

, 2010
We study the tangential case in 2-dimensional almost-Riemannian geometry. We analyse the connection with the Martinet case in sub-Riemannian geometry. We compute estimations of the exponential map which allow us to describe the conjugate locus and the ...
Bonnard, Bernard, Charlot, Grégoire, Ghezzi, Roberta, Janin, Gabriel   +3 more
core   +1 more source

Sub-Riemannian Geometry and Geodesics in Banach Manifolds [PDF]

The Journal of Geometric Analysis, 2019
In this paper, we define and study sub-Riemannian structures on Banach manifolds. We obtain extensions of the Chow-Rashevski theorem for exact controllability, and give conditions for the existence of a Hamiltonian geodesic flow despite the lack of a Pontryagin Maximum Principle in the infinite dimensional setting.
openaire   +4 more sources

Curvature exponent and geodesic dimension on Sard-regular Carnot groups

Analysis and Geometry in Metric Spaces
In this study, we characterize the geodesic dimension NGEO{N}_{{\rm{GEO}}} and give a new lower bound to the curvature exponent NCE{N}_{{\rm{CE}}} on Sard-regular Carnot groups.
Golo Sebastiano Nicolussi, Zhang Ye
doaj   +1 more source

Sub-Riemannian geometry and non-holonomic mechanics [PDF]

, 2001
Jair Koiller, Paulo Rogério Melo Rodrigues, P. Pitanga   +2 more
openalex   +1 more source

Good continuation in 3D: the neurogeometry of stereo vision

Frontiers in Computer Science
Classical good continuation for image curves is based on 2D position and orientation. It is supported by the columnar organization of cortex, by psychophysical experiments, and by rich models of (differential) geometry.
Maria Virginia Bolelli, Maria Virginia Bolelli, Giovanna Citti, Alessandro Sarti, Steven W. Zucker   +4 more
doaj   +1 more source

Metric lines in the jet space

Analysis and Geometry in Metric Spaces
In the realm of sub-Riemannian manifolds, a relevant question is: what are the metric lines (isometric embedding of the real line)? The space of kk-jets of a real function of one real variable xx, denoted by Jk(R,R){J}^{k}\left({\mathbb{R}},{\mathbb{R}}),
Bravo-Doddoli Alejandro
doaj   +1 more source

Sub-Riemannian geometry and time optimal control of three spin systems: Quantum gates and coherence transfer [PDF]

, 2002
Navin Khaneja, Steffen J. Glaser, Roger W. Brockett   +2 more
openalex   +1 more source