Results 71 to 80 of about 1,183,540 (276)
On semi-slant $\xi^\perp-$Riemannian submersions
, 2017 The aim of the present paper to define and study semi-slant $\xi^\perp-$Riemannian submersions from Sasakian manifolds onto Riemannian manifolds as a generalization of anti-invariant $\xi^\perp-$Riemannian submersions, semi-invariant $\xi^\perp ...
Akyol, Mehmet Akif, Sarı, Ramazan
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Interdisciplinary Medicine, EarlyView.Abstract Brain‐Computer Interface (BCI) based on motor imagery (MI) has attracted great interest as a new rehabilitation method for stroke. Riemannian geometry‐based classification algorithms are widely used in MI‐BCI due to their strong robustness and generalization capabilities.
Xinwei Sun +8 more
wiley +1 more source
Transversal Lightlike Submanifolds of Metallic Semi-Riemannian Manifolds
, 2018 The Metallic Ratio is fascinating topic that continually generated news ideas. A Riemannian manifold endowed with a Metallic structure will be called a Metallic Riemannian manifold.
Erdoğan, Feyza Esra
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Global and microlocal aspects of Dirac operators: Propagators and Hadamard states
Mathematische Nachrichten, EarlyView.Abstract We propose a geometric approach to construct the Cauchy evolution operator for the Lorentzian Dirac operator on Cauchy‐compact globally hyperbolic 4‐manifolds. We realize the Cauchy evolution operator as the sum of two invariantly defined oscillatory integrals—the positive and negative Dirac propagators—global in space and in time, with ...
Matteo Capoferri, Simone Murro
wiley +1 more source
The χ-Hessian Quotient for Riemannian Metrics
Axioms, 2021 Pseudo-Riemannian geometry and Hilbert–Schmidt norms are two important fields of research in applied mathematics. One of the main goals of this paper will be to find a link between these two research fields. In this respect, in the present paper, we will
Pişcoran Laurian-Ioan +3 more
doaj +1 more source
On the essential constants in Riemannian geometries [PDF]
Journal of Mathematical Physics, 2006 In the present work the problem of distinguishing between essential and spurious (i.e., absorbable) constants contained in a metric tensor field in a Riemannian geometry is considered. The contribution of the study is the presentation of a sufficient and necessary criterion, in terms of a covariant statement, which enables one to determine whether a ...
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Mathematical Methods in the Applied Sciences, Volume 48, Issue 6, Page 6912-6917, April 2025.ABSTRACT Nowadays, a substantial portion of investigations concerning the symmetry analysis of differential equations predominantly adhere to a framework comprising the following key procedures: (i) the derivation of symmetries, (ii) the determination of an optimal system, (iii) the utilization of these symmetries to construct invariants or ...
A. Paliathanasis +2 more
wiley +1 more source
On Jacobi fields and canonical connection in sub-Riemannian geometry [PDF]
, 2015 In sub-Riemannian geometry the coefficients of the Jacobi equation define curvature-like invariants. We show that these coefficients can be interpreted as the curvature of a canonical Ehresmann connection associated to the metric, first introduced in ...
D. Barilari, L. Rizzi
semanticscholar +1 more source
Pontryagin Calculus in Riemannian Geometry
, 2015 In this contribution, we study systems with a finite number of degrees of freedom as in robotics. A key idea is to consider the mass tensor associated to the kinetic energy as a metric in a Riemannian configuration space. We apply Pontryagin's framework to derive an optimal evolution of the control forces and torques applied to the mechanical system ...
Claude Vallée +4 more
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A UNITARY INVARIANT IN RIEMANNIAN GEOMETRY [PDF]
International Journal of Geometric Methods in Modern Physics, 2008 We introduce an invariant of Riemannian geometry which measures the relative position of two von Neumann algebras in Hilbert space, and which, when combined with the spectrum of the Dirac operator, gives a complete invariant of Riemannian geometry. We show that the new invariant plays the same role with respect to the spectral invariant as the Cabibbo–
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