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Álvaro K. Ramos

Publications and source records attributed to Álvaro K. Ramos.

5 recordsLinked to original sources

Dynamical Stability of Translating Solitons to Mean Curvature Flow in Hyperbolic Space

We develop the theory of translating solitons for the Mean Curvature Flow (MCF) in hyperbolic space of dimension $n+1\ge 3$. More specifically, we establish that horospheres are dynamically stable as radial graphical solutions to MCF. To that end, we construct rotationally invariant translators analogous to the winglike solitons introduced by Clutterbuck, Schnürer and Schulze, which serve as barriers in an argument based on White's avoidance principle and the strong maximum principle for parabolic PDEs.

math.DG↗

Elliptic Weingarten Hypersurfaces of Riemannian Products

Let $M^n$ be either a simply connected space form or a rank-one symmetric space of noncompact type. We consider Weingarten hypersurfaces of $M\times\mathbb R$, which are those whose principal curvatures $k_1,\dots ,k_n$ and angle function $θ$ satisfy a relation $W(k_1,\dots,k_n,θ^2)=0,$ being $W$ a differentiable function which is symmetric with respect to $k_1,\dots, k_n.$ When $\partial W/\partial k_i>0$ on the positive cone of $\mathbb R^n,$ a strictly convex Weingarten hypersurface determined by $W$ is said to be elliptic. We show that, for a certain class of Weingarten functions $W,$ there exist rotational strictly convex Weingarten hypersurfaces of $M\times\mathbb R$ which are either topological spheres or entire graphs over $M.$ We establish a Jellett-Liebmann-type theorem by showing that a compact, connected and elliptic Weingarten hypersurface of either $\mathbb S^n\times\mathbb R$ or $\mathbb H^n\times\mathbb R$ is a rotational embedded sphere. Other uniqueness results for complete elliptic Weingarten hypersurfaces of these ambient spaces are obtained. We also obtain existence results for constant scalar curvature hypersurfaces of $\mathbb S^n\times\mathbb R$ and $\mathbb H^n\times\mathbb R$ which are either rotational or invariant by translations (parabolic or hyperbolic). We apply our methods to give new proofs of the main results by Manfio and Tojeiro on the classification of constant sectional curvature hypersurfaces of $\mathbb S^n\times\mathbb R$ and $\mathbb H^n\times\mathbb R.$

math.DG↗

Modifications Preserving Hyperbolicity of Link Complements

Given a link in a 3-manifold such that the complement is hyperbolic, we provide two modifications to the link, called the chain move and the switch move, that preserve hyperbolicity of the complement, with only a relatively small number of manifold-link pair exceptions, which are also classified. These modifications provide a substantial increase in the number of known hyperbolic links in the 3-sphere and other 3-manifolds.

math.GT↗

Properly immersed surfaces in hyperbolic 3-manifolds

We study complete finite topology immersed surfaces $Σ$ in complete Riemannian $3$-manifolds $N$ with sectional curvature $K_N\leq -a^2\leq 0$, such that the absolute mean curvature function of $Σ$ is bounded from above by $a$ and its injectivity radius function is not bounded away from zero on each of its annular end representatives. We prove that such a surface $Σ$ must be proper in $N$ and its total curvature must be equal to $2πχ(Σ)$. If $N$ is a hyperbolic $3$-manifold of finite volume and $Σ$ is a properly immersed surface of finite topology with nonnegative constant mean curvature less than 1, then we prove that each end of $Σ$ is asymptotic (with finite positive multiplicity) to a totally umbilic annulus, properly embedded in $N$.

math.DG↗