Embedded area-constrained Willmore tori of small area in Riemannian three-manifolds I: Minimization

We construct embedded Willmore tori with small area constraint in Riemannian three-manifolds under some curvature condition used to prevent M\"obius degeneration. The construction relies on a Lyapunov-Schmidt reduction; to this aim we establish new geometric expansions of exponentiated small symmetric Clifford tori and analyze the sharp asymptotic behavior of degenerating tori under the action of the M\"obius group. In this first work we prove two existence results by minimizing or maximizing a suitable reduced functional, in particular we obtain embedded area-constrained Willmore tori (or, equivalently, toroidal critical points of the Hawking mass under area-constraint) in compact 3-manifolds with constant scalar curvature and in the double Schwarzschild space. In a forthcoming paper new existence theorems will be achieved via Morse theory.Comment: 41 pages. Final version to appear in the Proceedings of the London Math. Societ

Henbunho o mochiita hi senkei renritsu Shuredinga hoteishikikei, hi senkei Sukara-ba hoteishiki no kenkyu

制度:新 ; 報告番号:甲3280号 ; 学位の種類:博士(理学) ; 授与年月日:2011/3/15 ; 早大学位記番号:新558

On weak solutions to a fractional Hardy-H\'enon equation: Part II: Existence

This paper and [29] treat the existence and nonexistence of stable weak solutions to a fractional Hardy--H\'enon equation $(-\Delta)^s u = |x|^\ell |u|^{p-1} u$ in $\mathbb{R}^N$, where $0 -2s$, $p>1$, $N \geq 1$ and $N > 2s$. In this paper, when $p$ is critical or supercritical in the sense of the Joseph--Lundgren, we prove the existence of a family of positive radial stable solutions, which satisfies the separation property. We also show the multiple existence of the Joseph--Lundgren critical exponent for some $\ell \in (0,\infty)$ and $s \in (0,1)$, and this property does not hold in the case $s=1$.Comment: 52 page

Embedded area-constrained Willmore tori of small area in Riemannian three-manifolds II: Morse Theory

This is the second of a series of two papers where we construct embedded Willmore tori with small area constraint in Riemannian three-manifolds. In both papers the construction relies on a Lyapunov-Schmidt reduction, the difficulty being the M\"obius degeneration of the tori. In the first paper the construction was performed via minimization, here by Morse Theory; to this aim we establish new geometric expansions of the derivative of the Willmore functional on exponentiated small Clifford tori degenerating, under the action of the M\"obius group, to small geodesic spheres with a small handle. By using these sharp asymptotics we give sufficient conditions, in terms of the ambient curvature tensors and Morse inequalities, for having existence/multiplicity of embedded tori stationary for the Willmore functional under the constraint of prescribed (sufficiently small) area.Comment: Final version, to appear in the American Journal of Mathematic