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Related papers: Constrained Willmore Tori in the 4--Sphere

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Let $H^4$ denote the hyperbolic four-space. Given a bordered Riemann surface, $M$, we prove that every smooth conformal superminimal immersion $\overline M\to H^4$ can be approximated uniformly on compacts in $M$ by proper conformal…

Differential Geometry · Mathematics 2023-06-26 Franc Forstneric

The cohomological rigidity problem for toric orbifolds asks when an integral cohomology isomorphism implies a homotopy equivalence. In this paper we reformulate the cohomological rigidity problem in the context of $4$-dimensional toric…

Algebraic Topology · Mathematics 2026-05-01 Tyrone Cutler , Tseleung So

We define a suitably tame class of singular symplectic curves in 4-manifolds, namely those whose singularities are modeled on complex curve singularities. We study the corresponding symplectic isotopy problem, with a focus on rational…

Geometric Topology · Mathematics 2021-11-22 Marco Golla , Laura Starkston

We establish two classification theorems for Willmore surfaces in $\mathbb{S}^2 \times \mathbb{S}^2$. Firstly, we prove that a Willmore surface which is also minimal must be either a special complex curve given by a slice or a diagonal; or,…

Differential Geometry · Mathematics 2026-02-06 Xiaoling Chai , Shimpei Kobayashi , Changping Wang , Zhenxiao Xie

We consider the class of all conformal mappings from a compact Riemann surface into the threedimensional or fourdimensional Euclidean space. A sequence in this class with bounded Willmore functional is shown to have a sequence of conformal…

Differential Geometry · Mathematics 2007-05-23 Martin Ulrich Schmidt

We develop a bubble tree construction and prove compactness results for $W^{2,2}$ branched conformal immersions of closed Riemann surfaces, with varying conformal structures whose limit may degenerate, in a compact Riemannian manifold with…

Differential Geometry · Mathematics 2011-12-09 Jingyi Chen , Yuxiang Li

After the surface theory of M\"obius geometry, this study concerns a pair of conformally immersed surfaces in $n$-sphere. Two new invariants $\theta$ and $\rho$ associated with them are introduced as well as the notion of touch and…

Differential Geometry · Mathematics 2007-05-23 Xiang Ma

In this article, we use the harmonic sequence associated to a weakly conformal harmonic map $f:S\to S^6$ in order to determine explicit examples of linearly full almost complex 2-spheres of $S^6$ with at most two singularities. We prove…

Differential Geometry · Mathematics 2012-11-13 José Kenedy Martins

We prove that 3-dimensional ellipsoids invariant under a 2-torus action contain infinitely many distinct immersed minimal tori, with at most one exception. These minimal tori bifurcate from the 2-torus orbit of largest volume at a dense set…

Differential Geometry · Mathematics 2025-11-05 Renato G. Bettiol , Paolo Piccione

We list special graphs of degree 4 with at most 3 vertices (atoms from the theory of integrable hamiltonian systems) which could be represented by a union of closed geodesics on the one of the following surfaces with metric of constant…

Algebraic Topology · Mathematics 2014-12-31 I. Shnurnikov

The reduced system in the problem of the inertial motion of a rigid body with a fixed point (the Euler case) is equivalent, by the Maupertuis principle, to some geodesic flow on the 2-sphere. We describe the phase topology of this case…

Exactly Solvable and Integrable Systems · Physics 2014-08-27 Mikhail P. Kharlamov

We give a constructive proof of the existence of lower dimensional elliptic tori in nearly integrable Hamiltonian systems. In particular we adapt the classical Kolmogorov's normalization algorithm to the case of planetary systems, for which…

Mathematical Physics · Physics 2014-01-28 Antonio Giorgilli , Ugo Locatelli , Marco Sansottera

We prove that the group of Hamiltonian automorphisms of a symplectic 4-manifold contains only finitely many conjugacy classes of maximal compact tori with respect to the action of the full symplectomorphism group. We also extend to rational…

Symplectic Geometry · Mathematics 2011-04-26 Martin Pinsonnault

There are many four vertex type theorems appearing in the literature, coming in both smooth and discrete flavors. The most familiar of these is the classical theorem in differential geometry, which states that the curvature function of a…

Metric Geometry · Mathematics 2023-02-09 Wiktor Mogilski , Kyle Grant

We prove that a 3--dimensional hyperbolic cusp with convex polyhedral boundary is uniquely determined by its Gauss image. Furthermore, any spherical metric on the torus with cone singularities of negative curvature and all closed…

Differential Geometry · Mathematics 2009-08-17 François Fillastre , Ivan Izmestiev

It is shown that a superconformal surface with arbitrary codimension in flat Euclidean space has a (necessarily unique) dual superconformal surface if and only if the surface is S-Willmore, the latter a well-known necessary condition to…

Differential Geometry · Mathematics 2014-01-08 Marcos Dajczer , Theodoros Vlachos

Totally isotropic surfaces in $S^6$ are not necessarily Willmore surfaces. Therefore it is the first goal of this paper to derive a geometric characterization of totally isotropic Willmore two-spheres in $S^6$. This will naturally yield to…

Differential Geometry · Mathematics 2015-04-08 Peng Wang

In this paper, we show that an embedded Weingarten surface in S^3 of genus 1 must be rotationally symmetric, provided that certain structure conditions are satisfied. The argument involves an adaptation of our proof of Lawson's Conjecture…

Differential Geometry · Mathematics 2014-02-24 S. Brendle

We obtain in arbitrary codimension a removability result on the order of singularity of Willmore surfaces realising the width of Willmore min-max problems on spheres. As a consequence, out of the twelve families of non-planar minimal…

Analysis of PDEs · Mathematics 2019-04-23 Alexis Michelat , Tristan Rivière

Let $f:\mathbb{C}\rightarrow \mathbb{R}^3$ be complete Willmore immersion with $\int_{\Sigma}|A_f|^2<+\infty$. We will show that if $f$ is the limit of an embedded surface sequence, then $f$ is a plane. As an application, we prove that if…

Differential Geometry · Mathematics 2015-04-16 Yuxiang Li