Results 41 to 50 of about 341 (179)
Fortschritte der Physik, Volume 74, Issue 6, June 2026.ABSTRACT We present a clear, step‐by‐step method for counting degrees of freedom and identifying constraints in general field theories. This approach, grounded in the works of Einstein, Hilbert, Cartan, Kuranishi, and, more recently, Seiler, is neither Lagrangian nor Hamiltonian in nature. Instead, it applies directly to the field equations. We offer a
Lavinia Heisenberg
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On general helices and pseudo-riemannian manifolds
Communications, Faculty Of Science, University of Ankara Series A1Mathematics and Statistics, 1998 In a Riemannian manifold, a regular curve is called a general helix if is constant and its firs and second curvatures are not constant [4]. If its First and second curvatures are constant the third curvature is zero then the regular curve is called helix. For helices in a Lorentzian manifold, there is a research of T.
openaire +3 more sources
Seiberg-Witten Like Equations on Pseudo-Riemannian Spinc Manifolds with G2(2)∗ Structure
Advances in Mathematical Physics, 2016 We consider 7-dimensional pseudo-Riemannian spinc manifolds with structure group G2(2)∗. On such manifolds, the space of 2-forms splits orthogonally into components Λ2M=Λ72⊕Λ142.
Nülifer Özdemir, Nedim Deǧirmenci
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Covariance Estimation for Wide Data
WIREs Computational Statistics, Volume 18, Issue 2, June 2026.Covariance matrix estimation is fundamental to multivariate analysis, with applications spanning finance, genomics, climate science, and signal processing. This review synthesizes recent advances in high‐dimensional covariance estimation‐thresholding, linear and nonlinear shrinkage, graphical models, and random matrix theory‐under a unifying framework ...
Eran Raviv
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Commutative curvature operators over four-dimensional generalized symmetric
Sahand Communications in Mathematical Analysis, 2014 Commutative properties of four-dimensional generalized symmetric pseudo-Riemannian manifolds were considered. Specially, in this paper, we studied Skew-Tsankov and Jacobi-Tsankov conditions in 4-dimensional pseudo-Riemannian generalized symmetric ...
Ali Haji-Badali +2 more
doaj
Stochastic quantization on Lorentzian manifolds
Journal of High Energy Physics, 2021 We embed Nelson’s theory of stochastic quantization in the Schwartz-Meyer second order geometry framework. The result is a non-perturbative theory of quantum mechanics on (pseudo-)Riemannian manifolds.
Folkert Kuipers
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Autoparallels and the Inverse Problem of the Calculus of Variations
Fortschritte der Physik, Volume 74, Issue 5, May 2026.ABSTRACT We prove that autoparallel curves associated with a torsion‐free but not necessarily metric‐compatible affine connection can be derived from an action principle. We explicitly construct the action functional and show by standard variational techniques that it produces the desired equations.
Lavinia Heisenberg
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Characterizing Affine Vector Fields on Pseudo-Riemannian Manifolds
AxiomsWe study the characteristics of affine vector fields on pseudo-Riemannian manifolds and provide tensorial formulas that characterize these vector fields.
Norah Alshehri, Mohammed Guediri
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Mathematics, 2023 We obtain some generalized Minkowski type integral formulas for compact Riemannian (resp., spacelike) hypersurfaces in Riemannian (resp., Lorentzian) manifolds in the presence of an arbitrary vector field that we assume to be timelike in the case where ...
Norah Alessa, Mohammed Guediri
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A Comprehensive Survey on Parallel Submanifolds in Riemannian and Pseudo-Riemannian Manifolds
Axioms, 2019 A submanifold of a Riemannian manifold is called a parallel submanifold if its second fundamental form is parallel with respect to the van der Waerden−Bortolotti connection.
Bang-Yen Chen
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