Results 21 to 30 of about 1,492 (57)

On the problem of prescribing weighted scalar curvature and the weighted Yamabe flow

open access: yesAnalysis and Geometry in Metric Spaces, 2023
The weighted Yamabe problem introduced by Case is the generalization of the Gagliardo-Nirenberg inequalities to smooth metric measure spaces. More precisely, given a smooth metric measure space (M,g,e−ϕdVg,m)\left(M,g,{e}^{-\phi }{\rm{d}}{V}_{g},m), the ...
Ho Pak Tung, Shin Jinwoo
doaj   +1 more source

Limits of Riemannian 4‐manifolds and the symplectic geometry of their twistor spaces

open access: yesTransactions of the London Mathematical Society, Volume 4, Issue 1, Page 100-109, December 2017., 2017
Abstract The twistor space of a Riemannian 4‐manifold carries two almost complex structures, J+ and J−, and a natural closed 2‐form ω. This article studies limits of manifolds for which ω tames either J+ or J−. This amounts to a curvature inequality involving self‐dual Weyl curvature and Ricci curvature, and which is satisfied, for example, by all anti‐
Joel Fine
wiley   +1 more source

Weakly Noncollapsed RCD Spaces with Upper Curvature Bounds

open access: yesAnalysis and Geometry in Metric Spaces, 2019
We show that if a CD(K, n) space (X, d, f ℋn) with n ≥ 2 has curvature bounded above by κ in the sense of Alexandrov then f is constant.
Kapovitch Vitali, Ketterer Christian
doaj   +1 more source

Smooth long‐time existence of Harmonic Ricci Flow on surfaces

open access: yesJournal 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

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

open access: yesInternational 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   +2 more
wiley   +1 more source

Volume Bounds for the Quantitative Singular Strata of Non Collapsed RCD Metric Measure Spaces

open access: yesAnalysis and Geometry in Metric Spaces, 2019
The aim of this note is to generalize to the class of non collapsed RCD(K, N) metric measure spaces the volume bound for the effective singular strata obtained by Cheeger and Naber for non collapsed Ricci limits in [13].
Antonelli Gioacchino   +2 more
doaj   +1 more source

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

open access: yesInternational 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

open access: yesInternational 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

open access: yesAdvanced 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

open access: yesInternational 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

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