Results 21 to 30 of about 524 (55)

Prescribing eigenvalues of the Dirac operator

open access: yes, 2005
In this note we show that every compact spin manifold of dimension $\geq 3$ can be given a Riemannian metric for which a finite part of the spectrum of the Dirac operator consists of arbitrarily prescribed eigenvalues with multiplicity 1.Comment: To ...
Bär   +7 more
core   +1 more source

On subsolutions and concavity for fully nonlinear elliptic equations

open access: yesAdvanced Nonlinear Studies
Subsolutions and concavity play critical roles in classical solvability, especially a priori estimates, of fully nonlinear elliptic equations. Our first primary goal in this paper is to explore the possibility to weaken the concavity condition.
Guan Bo
doaj   +1 more source

Lattice calculations on the spectrum of Dirac and Dirac-K\"ahler operators

open access: yes, 2006
We present a matrix technique to obtain the spectrum and the analytical index of some elliptic operators defined on compact Riemannian manifolds. The method uses matrix representations of the derivative which yield exact values for the derivative of a ...
Campos R. G.   +8 more
core   +1 more source

Deformations of 2k-Einstein structures

open access: yes, 2010
It is shown that the space of infinitesimal deformations of 2k-Einstein structures is finite dimensional at compact non-flat space forms. Moreover, spherical space forms are shown to be rigid in the sense that they are isolated in the corresponding ...
Berger   +10 more
core   +1 more source

Blowing-up solutions concentrated along minimal submanifolds for some supercritical Hamiltonian systems on Riemannian manifolds

open access: yesAdvances in Nonlinear Analysis
Let (ℳ,g)\left({\mathcal{ {\mathcal M} }},g) and (K,κ)\left({\mathcal{K}},\kappa ) be two Riemannian manifolds of dimensions NN and mm, respectively. Let ω∈C2(ℳ)\omega \in {C}^{2}\left({\mathcal{ {\mathcal M} }}) satisfy ω>0\omega \gt 0.
Chen Wenjing, Wang Zexi
doaj   +1 more source

Comparison formulas for total mean curvatures of Riemannian hypersurfaces

open access: yesAdvanced Nonlinear Studies
We devise some differential forms after Chern to compute a family of formulas for comparing total mean curvatures of nested hypersurfaces in Riemannian manifolds.
Ghomi Mohammad
doaj   +1 more source

Infinitely many free or prescribed mass solutions for fractional Hartree equations and Pohozaev identities

open access: yesAdvanced Nonlinear Studies
In this paper we study the following nonlinear fractional Hartree (or Choquard-Pekar) equation (−Δ)su+μu=(Iα*F(u))F′(u) inRN, ${\left(-{\Delta}\right)}^{s}u+\mu u=\left({I}_{\alpha }{\ast}F\left(u\right)\right){F}^{\prime }\left(u\right)\quad \text{in} {\
Cingolani Silvia   +2 more
doaj   +1 more source

Overtwisted energy-minimizing curl eigenfields

open access: yes, 2015
We consider energy-minimizing divergence-free eigenfields of the curl operator in dimension three from the perspective of contact topology. We give a negative answer to a question of Etnyre and the first author by constructing curl eigenfields which ...
Arnold V   +14 more
core   +1 more source

Examples of non-isolated blow-up for perturbations of the scalar curvature equation on non locally conformally flat manifolds [PDF]

open access: yes, 2014
Solutions to scalar curvature equations have the property that all possible blow-up points are isolated, at least in low dimensions. This property is commonly used as the first step in the proofs of compactness. We show that this result becomes false for
Robert, Frédéric, Vétois, Jérôme
core   +2 more sources

On the Riemannian Penrose inequality with charge and the cosmic censorship conjecture [PDF]

open access: yes, 2012
We note an area-charge inequality orignially due to Gibbons: if the outermost horizon $S$ in an asymptotically flat electrovacuum initial data set is connected then $|q|\leq r$, where $q$ is the total charge and $r=\sqrt{A/4\pi}$ is the area radius of $S$
Khuri, Marcus A   +2 more
core  

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