Results 11 to 20 of about 112 (98)
Transversal Jacobi Operators in Almost Contact Manifolds
Mathematics, 2020 Along a transversal geodesic γ whose tangent belongs to the contact distribution D, we define the transversal Jacobi operator Rγ=R(·,γ˙)γ˙ on an almost contact Riemannian manifold M.
Jong Taek Cho, Makoto Kimura
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Generating Curves of Minimal Ruled Real Hypersurfaces in a Nonflat Complex Space Form [PDF]
Canadian Mathematical Bulletin, 2019 AbstractWe first provide a necessary and sufficient condition for a ruled real hypersurface in a nonflat complex space form to have constant mean curvature in terms of integral curves of the characteristic vector field on it. This yields a characterization of minimal ruled real hypersurfaces by circles.
Maeda, Sadahiro +2 more
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Open Mathematics, 2015 In this paper three dimensional real hypersurfaces in non-flat complex space forms whose k-th Cho operator with respect to the structure vector field ξ commutes with the structure Jacobi operator are classified.
Panagiotidou Konstantina +1 more
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On ruled real hypersurfaces in a complex space form
Tsukuba Journal of Mathematics, 1993 A real hypersurface \(M\) of a complex space form \(N\) is said to be ruled if \(M\) is foliated by one-codimensional totally geodesic complex submanifolds of \(N\). The authors provide a sufficient condition for a real hypersurface in a non-flat complex space form to be ruled.
Ahn, Seong-Soo +2 more
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Ruled real hypersurfaces having the same sectional curvature as that of an ambient nonflat complex space form [PDF]
Kodai Mathematical Journal, 2016 Ruled real hypersurfaces in a nonflat complex space form $\tilde{M}_n(c) (n ≧ 2)$ are obtained by having a one-codimensional foliation whose leaves are totally geodesic complex hypersurfaces of the ambient space. Motivated by a fact that the sectional curvature $K$ of every ruled real hypersurface $M$ in $\tilde{M}_n(c) (n ≧ 3)$ satisfies $|c/4| ≦ |K(X,
Maeda, Sadahiro +2 more
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Sectional curvatures of ruled real hypersurfaces in a complex hyperbolic space
Differential Geometry and its Applications, 2017 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Maeda, Sadahiro, Tanabe, Hiromasa
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Rational points on even‐dimensional Fermat cubics
Transactions of the London Mathematical Society, Volume 13, Issue 1, December 2026.Abstract We show that even‐dimensional Fermat cubic hypersurfaces are rational over any field of characteristic not equal to three, by constructing explicit rational parameterizations with polynomials of low degree. As a byproduct of our rationality constructions, we obtain estimates for the number of their rational points over a number field and ...
Alex Massarenti
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Safe Stabilization Using Non‐Smooth Control Lyapunov Barrier Function
International Journal of Robust and Nonlinear Control, Volume 36, Issue 11, Page 5823-5835, 25 July 2026.ABSTRACT This paper addresses the challenge of safe stabilization, ensuring the system state reaches the origin while avoiding unsafe state regions. Existing approaches that rely on smooth Lyapunov barrier functions often fail to guarantee a feasible controller. To overcome this limitation, we introduce the non‐smooth control Lyapunov barrier function (
Jianglin Lan +3 more
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Affine hypersurfaces and superintegrable systems
Journal of the London Mathematical Society, Volume 114, Issue 1, July 2026.Abstract It was recently shown that under mild assumptions, second‐order conformally superintegrable systems can be encoded in a (0,3)‐tensor, called structure tensor. For abundant systems, this approach led to algebraic integrability conditions that essentially allow one to restore a system from the knowledge of its structure tensor in a point on the ...
Vicente Cortés, Andreas Vollmer
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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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