Results 21 to 30 of about 1,619 (92)

On the topology of closed manifolds with quasi-constant sectional curvature

Journal de l'École polytechnique. Mathématiques, 2019
We prove that closed manifolds admitting a metric whose sectional curvature is locally quasi-constant are graphs of space forms. In the more general setting of QC space where sets of isotropic points are arbitrary, under suitable positivity assumption ...
L. Funar
semanticscholar   +1 more source

Smooth long‐time existence of Harmonic Ricci Flow on surfaces

Journal of the London Mathematical Society, Volume 95, Issue 1, Page 277-304, February 2017., 2017
Abstract We prove that at a finite singular time for the Harmonic Ricci Flow on a surface of positive genus both the energy density of the map component and the curvature of the domain manifold have to blow up simultaneously. As an immediate consequence, we obtain smooth long‐time existence for the Harmonic Ricci Flow with large coupling constant.
Reto Buzano, Melanie Rupflin
wiley   +1 more source

Spectral Calculus and Lipschitz Extension for Barycentric Metric Spaces

Analysis and Geometry in Metric Spaces, 2013
The metric Markov cotype of barycentric metric spaces is computed, yielding the first class of metric spaces that are not Banach spaces for which this bi-Lipschitz invariant is understood.
Mendel Manor, Naor Assaf
doaj   +1 more source

On the geometry of Riemannian manifolds with a Lie structure at infinity

International Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 4, Page 161-193, 2004., 2004
We study a generalization of the geodesic spray and give conditions for noncomapct manifolds with a Lie structure at infinity to have positive injectivity radius. We also prove that the geometric operators are generated by the given Lie algebra of vector fields.
Bernd Ammann, Robert Lauter, Victor Nistor   +2 more
wiley   +1 more source

Bakry-Émery Conditions on Almost Smooth Metric Measure Spaces

Analysis and Geometry in Metric Spaces, 2018
In this short note, we give a sufficient condition for almost smooth compact metric measure spaces to satisfy the Bakry-Émery condition BE(K, N). The sufficient condition is satisfied for the glued space of any two (not necessary same dimensional) closed
Honda Shouhei
doaj   +1 more source

Skew‐symmetric vector fields on a CR‐submanifold of a para‐Kählerian manifold

International Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 10, Page 535-540, 2004., 2004
We deal with a CR‐submanifold M of a para‐Kählerian manifold M˜, which carries a J‐skew‐symmetric vector field X. It is shown that X defines a global Hamiltonian of the symplectic form Ω on M⊤ and JX is a relative infinitesimal automorphism of Ω. Other geometric properties are given.
Adela Mihai, Radu Rosca
wiley   +1 more source

On the projections of Laplacians under Riemannian submersions

International Journal of Mathematics and Mathematical Sciences, Volume 25, Issue 1, Page 33-42, 2001., 2001
We give a condition on Riemannian submersions from a Riemannian manifold M to a Riemannian manifold N which will ensure that it induces a differential operator on N from the Laplace‐Beltrami operator on M. Equivalently, this condition ensures that a Riemannian submersion maps Brownian motion to a diffusion.
Huiling Le
wiley   +1 more source

Concentration-Compactness Principle for Trudinger–Moser’s Inequalities on Riemannian Manifolds and Heisenberg Groups: A Completely Symmetrization-Free Argument

Advanced Nonlinear Studies, 2021
The concentration-compactness principle for the Trudinger–Moser-type inequality in the Euclidean space was established crucially relying on the Pólya–Szegő inequality which allows to adapt the symmetrization argument.
Li Jungang, Lu Guozhen, Zhu Maochun
doaj   +1 more source

Quaternion CR‐submanifolds of a quaternion Kaehler manifold

International Journal of Mathematics and Mathematical Sciences, Volume 27, Issue 1, Page 27-37, 2001., 2001
We study the quaternion CR‐submanifolds of a quaternion Kaehler manifold. More specifically we study the properties of the canonical structures and the geometry of the canonical foliations by using the Bott connection and the index of a quaternion CR‐submanifold.
Bassil J. Papantoniou, M. Hasan Shahid
wiley   +1 more source

The β-Flatness Condition in CR Spheres

Advanced Nonlinear Studies, 2017
This work is an adaptation of one of the methods based on the variational critical points at infinity theory of Abbas Bahri [1, 3, 2, 4, 5, 6, 7, 8] to the Cauchy–Riemann settings.
Gamara Najoua, Hafassa Boutheina
doaj   +1 more source