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Related papers: An index bound for smooth umbilic points

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We show that for an immersed two-sided minimal surface in $R^3$, there is a lower bound on the index depending on the genus and number of ends. Using this, we show the nonexistence of an embedded minimal surface in $R^3$ of index $2$, as…

Differential Geometry · Mathematics 2019-07-01 Otis Chodosh , Davi Maximo

We prove that under some assumptions on the mean curvature the set of umbilical points of an immersed surface in a $3$-dimensional space form has positive measure. In case of an immersed sphere our result can be seen as a generalization of…

Differential Geometry · Mathematics 2021-01-21 Giovanni Catino , Alberto Roncoroni , Luigi Vezzoni

We consider unbranched Willmore surfaces in the Euclidean space that arise as inverted complete minimal surfaces with embedded planar ends. Several statements are proven about upper and lower bounds on the Morse Index - the number of…

Differential Geometry · Mathematics 2019-05-23 Jonas Hirsch , Elena Mäder-Baumdicker

In this note a definition of umbilic point at infinity is proposed, at least for surfaces that are homogeneous polynomial graphs over a plane in Euclidean 3-space. This is a stronger definition than that of Toponogov in his study of…

Differential Geometry · Mathematics 2024-05-13 Brendan Guilfoyle

In this paper we classify all singular irreducible symplectic surfaces, i.e., compact, connected complex surfaces with canonical singularities that have a holomorphic symplectic form $\sigma$ on the smooth locus, and for which every finite…

Algebraic Geometry · Mathematics 2026-03-23 Alice Garbagnati , Matteo Penegini , Arvid Perego

We show that in any triangulated 3-manifold, every index n topologically minimal surface can be transformed to a surface which has local indices (as computed in each tetrahedron) that sum to at most n. This generalizes classical theorems of…

Geometric Topology · Mathematics 2012-10-18 David Bachman

In this paper we propose a computational approach to proving the Birkhoff conjecture on the restricted three-body problem, which asserts the existence of a disk-like global surface of section. Birkhoff had conjectured this surface of…

Symplectic Geometry · Mathematics 2025-02-18 Chankyu Joung , Otto van Koert

The smooth equimultiple locus of embedded algebroid surfaces appears naturally in many resolution process, both classical and modern. In this paper we explore how it changes by blowing--up.

Algebraic Geometry · Mathematics 2010-05-31 R. Piedra , Jose M. Tornero

We give a full classification of higher order parallel surfaces in three-dimensional homogeneous spaces with four-dimensional isometry group, i.e. in the so-called Bianchi-Cartan-Vranceanu family. This gives a positive answer to a…

Differential Geometry · Mathematics 2008-02-08 Joeri Van der Veken

We define a geometric invariant and an index (+1 or -1) for projective umbilics of smooth surfaces. We prove that the sum of the indices of the projective umbilics inside a connected component H of the hyperbolic domain remains constant in…

Differential Geometry · Mathematics 2019-11-06 Ricardo Uribe-Vargas

In bounded domains, without any geometric conditions, we study the existence and uniqueness of globally Lipschitz and interior strong C^{1,1}, (and classical C^2), solutions of general semilinear oblique boundary value problems for…

Analysis of PDEs · Mathematics 2018-12-05 Feida Jiang , Neil S Trudinger

We prove a conjecture of Toponogov on complete convex planes, namely that such planes must contain an umbilic point, albeit at infinity. Our proof is indirect. It uses Fredholm regularity of an associated Riemann-Hilbert boundary value…

Differential Geometry · Mathematics 2024-10-01 Brendan Guilfoyle , Wilhelm Klingenberg

We prove that the Almgren-Pitts 6-width of the unit 3-ball is less than $2\pi$. We also prove that there exists a free boundary minimal surface in the unit 3-ball that has genus at most 1, index at most 5, area less than $2\pi$, and is not…

Differential Geometry · Mathematics 2023-05-17 Adrian Chun-Pong Chu

Carath\'eodory's conjecture has long been regarded as one of the central problems in the classical theory of convex surfaces. In this paper, we establish an index formula for hemispheres of convex closed surfaces under $C^2$-regularity. The…

Differential Geometry · Mathematics 2026-01-06 Naoya Ando , Masaaki Umehara

The topology of the orbit space, $Y$, for the action of the complex conjugation on a complex surface, $X$, defined over reals, is studied. I give a criterion for blow-up stable triviality of $Y$ (which implies vanishing of its…

Geometric Topology · Mathematics 2007-05-23 Sergey Finashin

We study the structure of complex points on real surfaces, embedded into complex Elliptic surfaces. We show, for example, that any compact surface has a totally real embedding into a blow-up of a K3 surface. We also exhibit smooth disc…

Complex Variables · Mathematics 2015-02-24 Marko Slapar

We prove a structural theorem that provides a precise local picture of how a sequence of closed embedded minimal hypersurfaces with uniformly bounded index (and volume if the ambient dimension is greater than three) in a Riemannian manifold…

Differential Geometry · Mathematics 2019-07-01 Otis Chodosh , Daniel Ketover , Davi Maximo

We give a lower bound for the numerical index of two-dimensional real spaces with absolute and symmetric norm. This allows us to compute the numerical index of the two-dimensional real $L_p$-space for $3/2\leq p\leq 3$.

Functional Analysis · Mathematics 2020-05-04 Javier Merí , Alicia Quero

We study trapped surfaces from the point of view of local isometric embedding into three-dimensional Riemannian manifolds. When a two-surface is embedded into three-dimensional Euclidean space, the problem of finding all surfaces applicable…

General Relativity and Quantum Cosmology · Physics 2018-09-26 Donato Bini , Giampiero Esposito

For any smooth Riemannian metric on an $(n+1)$-dimensional compact manifold with boundary $(M,\partial M)$ where $3\leq (n+1)\leq 7$, we establish general upper bounds for the Morse index of free boundary minimal hypersurfaces produced by…

Differential Geometry · Mathematics 2019-07-30 Qiang Guang , Martin Man-chun Li , Zhichao Wang , Xin Zhou