Results 31 to 40 of about 784 (176)

On real hypersurfaces in quaternionic projective space with 𝒟⊥-recurrent second fundamental tensor

International Journal of Mathematics and Mathematical Sciences, 1999
In this paper, we give a complete classification of real hypersurfaces in a quaternionic projective space QPm with 𝒟⊥-recurrent second fundamental tensor under certain condition on the orthogonal distribution 𝒟.
Young Jin Suh, Juan De Dios Pérez
doaj   +1 more source

A Characterization of Ruled Real Hypersurfaces in Non-Flat Complex Space Forms

Mathematics, 2020
The Levi-Civita connection and the k-th generalized Tanaka-Webster connection are defined on a real hypersurface M in a non-flat complex space form.
George Kaimakamis, Konstantina Panagiotidou, Juan de Dios Pérez   +2 more
doaj   +1 more source

A New Class of Contact Pseudo Framed Manifolds with Applications

International Journal of Mathematics and Mathematical Sciences, 2021
In this paper, we introduce a new class of contact pseudo framed (CPF)-manifolds M,g,f,λ,ξ by a real tensor field f of type 1,1, a real function λ such that f3=λ2f where ξ is its characteristic vector field. We prove in our main Theorem 2 that M admits a
K. L. Duggal
doaj   +1 more source

Peskine Sixfolds and Debarre–Voisin Fourfolds With Associated Cubic Fourfolds

Mathematische Nachrichten, EarlyView.
ABSTRACT We develop the notion of Peskine sixfolds with associated K3 surfaces and cubic fourfolds and work out numerical conditions for when these associations occur. In discriminant 24, the first family for which there is an associated cubic fourfold, we identify the cubic explicitly.
Corey Brooke, Laure Flapan, Sarah Frei, Lisa Marquand   +3 more
wiley   +1 more source

The Shape Operator of Real Hypersurfaces in S⁶(1)

Mathematics
The aim of the paper is to present two results concerning real hypersurfaces in the six-dimensional sphere S6(1). More precisely, we prove that real hypersurfaces with the Lie-parallel shape operator A must be totally geodesic hyperspheres. Additionally,
Djordje Kocić, Miroslava Antić
doaj   +1 more source

Characterizing Spheres in ℂ2 by Their Levi Curvature: A Result à la Jellett

Bruno Pini Mathematical Analysis Seminar, 2017
We investigate rigidity problems for a class of real hypersurfaces in ℂ2 with constant Levi curvature. We present a recent result obtained in A Jellett type theorem for the Levi curvature (2017) in collaboration with V.
Giulio Tralli
doaj   +1 more source

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, Jaime A. Moreno, Johann Reger   +2 more
wiley   +1 more source

Real Hypersurfaces in complex hyperbolic two-plane Grassmannians with commuting shape operator

Open Mathematics, 2015
In this paper we prove a non-existence of real hypersurfaces in complex hyperbolic two-plane Grassmannians SU2.m/S(U2·Um), m≥3, whose structure tensors {ɸi}i=1,2,3 commute with the shape operator.
de Dios Pérez Juan, Suh Young Jin, Woo Changhwa   +2 more
doaj   +1 more source

Quasi-Einstein Hypersurfaces of Complex Space Forms

Advances in Mathematical Physics, 2020
Based on a well-known fact that there are no Einstein hypersurfaces in a nonflat complex space form, in this article, we study the quasi-Einstein condition, which is a generalization of an Einstein metric, on the real hypersurface of a nonflat complex ...
Xuehui Cui, Xiaomin Chen
doaj   +1 more source

Gradient‐ and Newton‐Based Unit Vector Extremum Seeking Control

International Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT This paper proposes new methods for stable and efficient convergence in multivariable extremum seeking control (ESC) using sliding mode techniques. Inspired by classical sliding modes and finite‐time control, the approach integrates these ideas into gradient‐ and Newton‐based ESC schemes with sinusoidal perturbations.
Roberto Luo, Victor Hugo Pereira Rodrigues, Tiago Roux Oliveira, Miroslav Krstic   +3 more
wiley   +1 more source