Results 41 to 50 of about 73,367 (201)
On the equivalence of two curvature conditions for Lorentzian hypersurfaces
Arab Journal of Mathematical Sciences, 2017 Let n≥3. We show that semi-symmetry and Ricci-semisymmetry conditions are equivalent for any n-dimensional Lorentzian hypersurface in a Lorentzian space form with nonzero curvature.
Mohammed Guediri, Norah Alshehri
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Optimal Gain Selection for the Arbitrary‐Order Homogeneous Differentiator
International Journal of Robust and Nonlinear Control, EarlyView.ABSTRACT Differentiation of noisy signals is a relevant and challenging task. Widespread approaches are the linear high‐gain observer acting as a differentiator and Levant's robust exact differentiator with a discontinuous right‐hand side. We consider the family of arbitrary‐order homogeneous differentiators, which includes these special cases.
Benjamin Calmbach +2 more
wiley +1 more source
$F$-thresholds of hypersurfaces [PDF]
Transactions of the American Mathematical Society, 2009 We continue our study of F-thresholds begun in math/0607660 by an in depth analysis of the hypersurface case. We use the D--module theoretic description of generalized test ideals which allows us to show that in any F--finite regular ring the F-thresholds of hypersurfaces are discrete and rational (in math/0607660 the finite type over a field case was ...
Blickle, Manuel +2 more
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Differential Geometry and Matrix-Based Generalizations of the Pythagorean Theorem in Space Forms
MathematicsIn this work, we consider Pythagorean triples and quadruples using fundamental form matrices of hypersurfaces in three- and four-dimensional space forms and illustrate various figures. Moreover, we generalize that an immersed hypersphere Mn with radius r
Erhan Güler +2 more
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Safe Stabilization Using Non‐Smooth Control Lyapunov Barrier Function
International Journal of Robust and Nonlinear Control, EarlyView.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
wiley +1 more source
Lightlike Hypersurfaces and Canal Hypersurfaces of Lorentzian Surfaces
Abstract and Applied Analysis, 2014 The lightlike hypersurfaces in semi-Euclidean space are of special interest in Relativity Theory. In particular, the singularities of these lightlike hypersurfaces provide good models for the study of different horizon types. And we obtain some geometrical propositions of the canal hypersurfaces of Lorentzian surfaces.
Sun, Jianguo, Pei, Donghe
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Vertical Deformation Mapping: Steering Optimiser Toward Flat Minima
CAAI Transactions on Intelligence Technology, EarlyView.ABSTRACT Standard deep learning optimisation is typically conducted on shape‐fixed loss surfaces. However, shape‐fixed loss surfaces may impede optimisers from reaching flat regions closely associated with strong generalisation. In this work, we propose a new paradigm named deformation mapping to deform the loss surface during optimisation.
Liangming Chen +4 more
wiley +1 more source
Bernstein-type theorems in hypersurfaces with constant mean curvature
Anais da Academia Brasileira de Ciências, 2000 By using the nodal domains of some natural function arising in the study of hypersurfaces with constant mean curvature we obtain some Bernstein-type theorems.
MANFREDO P. DO CARMO, DETANG ZHOU
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On a property of W4 -manifolds
Дифференциальная геометрия многообразий фигур, 2020 The properties of almost Hermitian manifolds belonging to the Gray — Hervella class W4 are considered. The almost Hermitian manifolds of this class were studied by such outstanding geometers like Alfred Gray, Izu Vaisman, and Vadim Feodorovich Kirichenko.
M.B. Banaru
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On the stability of minimal cones in warped products
, 2014 In a seminal paper published in $1968$, J. Simons proved that, for $n\leq 5$, the Euclidean (minimal) cone $CM$, built on a closed, oriented, minimal and non totally geodesic hypersurface $M^n$ of $\mathbb S^{n+1}$ is unstable.
Bezerra, K. S., Caminha, A., Lima, B. P.
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