scholarly journals Free boundary minimal surfaces in the unit ball with low cohomogeneity

2016 ◽  
Vol 145 (4) ◽  
pp. 1671-1683 ◽  
Author(s):  
Brian Freidin ◽  
Mamikon Gulian ◽  
Peter McGrath
Keyword(s):  
Free Boundary ◽  
Unit Ball ◽  
Minimal Surfaces

scholarly journals Large Steklov eigenvalues via homogenisation on manifolds

2021 ◽  
Author(s):  
Alexandre Girouard ◽  
Jean Lagacé
Keyword(s):  
Free Boundary ◽  
Unit Ball ◽  
Lower Bounds ◽  
Upper Bound ◽  
Minimal Surfaces ◽  
Constant Weight ◽  
Steklov Eigenvalue ◽  
Laplace Eigenvalues ◽  
Steklov Eigenvalues ◽  
Steklov Eigenfunctions

AbstractUsing methods in the spirit of deterministic homogenisation theory we obtain convergence of the Steklov eigenvalues of a sequence of domains in a Riemannian manifold to weighted Laplace eigenvalues of that manifold. The domains are obtained by removing small geodesic balls that are asymptotically densely uniformly distributed as their radius tends to zero. We use this relationship to construct manifolds that have large Steklov eigenvalues. In dimension two, and with constant weight equal to 1, we prove that Kokarev’s upper bound of $$8\pi $$ 8 π for the first nonzero normalised Steklov eigenvalue on orientable surfaces of genus 0 is saturated. For other topological types and eigenvalue indices, we also obtain lower bounds on the best upper bound for the eigenvalue in terms of Laplace maximisers. For the first two eigenvalues, these lower bounds become equalities. A surprising consequence is the existence of free boundary minimal surfaces immersed in the unit ball by first Steklov eigenfunctions and with area strictly larger than $$2\pi $$ 2 π . This was previously thought to be impossible. We provide numerical evidence that some of the already known examples of free boundary minimal surfaces have these properties and also exhibit simulations of new free boundary minimal surfaces of genus zero in the unit ball with even larger area. We prove that the first nonzero Steklov eigenvalue of all these examples is equal to 1, as a consequence of their symmetries and topology, so that they are consistent with a general conjecture by Fraser and Li. In dimension three and larger, we prove that the isoperimetric inequality of Colbois–El Soufi–Girouard is sharp and implies an upper bound for weighted Laplace eigenvalues. We also show that in any manifold with a fixed metric, one can construct by varying the weight a domain with connected boundary whose first nonzero normalised Steklov eigenvalue is arbitrarily large.

Approximation of minimal surfaces with free boundaries: convergence results

2018 ◽  
Vol 39 (3) ◽  
pp. 1391-1420
Author(s):  
Tristan Jenschke
Keyword(s):  
Free Boundary ◽  
Boundary Problem ◽  
Free Boundary Problem ◽  
Minimal Surfaces ◽  
Approximate Solutions ◽  
Variational Problems ◽  
Free Boundaries ◽  
Convergence Estimate ◽  
Convergence Results ◽  
Discrete Finite Element

Abstract In a previous paper we developed a penalty method to approximate solutions of the free boundary problem for minimal surfaces by solutions of certain variational problems depending on a parameter $\lambda $. There we showed existence and $C^2$-regularity of these solutions as well as convergence to the solution of the free boundary problem for $\lambda \to \infty $. In this paper we develop a fully discrete finite element procedure for approximating solutions of these variational problems and prove a convergence estimate, which includes an order of convergence with respect to the grid size.

Optimal boundary regularity for minimal surfaces with a free boundary

1981 ◽  
Vol 33 (3-4) ◽  
pp. 357-364 ◽  
Author(s):  
Stefan Hildebrandt ◽  
Johannes C. C. Nitsche
Keyword(s):  
Free Boundary ◽  
Minimal Surfaces ◽  
Boundary Regularity ◽  
Optimal Boundary

scholarly journals Free boundary minimal surfaces in the unit 3-ball

2017 ◽  
Vol 154 (3-4) ◽  
pp. 359-409 ◽  
Author(s):  
Abigail Folha ◽  
Frank Pacard ◽  
Tatiana Zolotareva
Keyword(s):  
Free Boundary ◽  
Minimal Surfaces

scholarly journals Sharp Area Bounds for Free Boundary Minimal Surfaces in Conformally Euclidean Balls

2018 ◽  
Vol 2020 (18) ◽  
pp. 5630-5641 ◽  
Author(s):  
Brian Freidin ◽  
Peter McGrath
Keyword(s):  
Free Boundary ◽  
Minimal Surface ◽  
Minimal Surfaces ◽  
Geodesic Ball ◽  
Euclidean Setting

Abstract We prove that the area of a free boundary minimal surface $\Sigma ^2 \subset B^n$, where $B^n$ is a geodesic ball contained in a round hemisphere $\mathbb{S}^n_+$, is at least as big as that of a geodesic disk with the same radius as $B^n$; equality is attained only if $\Sigma $ coincides with such a disk. More generally, we prove analogous results for a class of conformally euclidean ambient spaces. This follows works of Brendle and Fraser–Schoen in the euclidean setting.

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