The paper characterizes geometrically finite surfaces via geodesic covers.
problem Characterizing geometrically finite surfaces.
method Study of geodesic covers of Fuchsian groups and their metric properties.
result Finiteness of geodesic covers characterizes geometrically finiteness.
The paper proves geometrical finiteness for automorphism groups of K3 surfaces and related varieties.
problem Establishing geometrical finiteness for automorphism groups of K3 surfaces and related varieties.
method Using cone conjecture, the paper establishes geometrical finiteness for the natural isometric actions of automorphism groups on hyperbolic spaces.
result Automorphism groups of K3 surfaces and related varieties are non-positively curved and relatively hyperbolic.
The systole size affects the smallest eigenvalue of hyperbolic surfaces.
problem Determining the smallest eigenvalue of hyperbolic surfaces based on their systole size.
method Analyzing the relationship between systole size and the smallest eigenvalue of Laplacian on hyperbolic surfaces.
result If the systole of a hyperbolic surface is greater than 3.46, then the smallest negative eigenvalue is greater than 1/4.
Extensions of Veech groups using hierarchical hyperbolic spaces.
problem Generalizing Veech groups to non-lattice cases.
method Using a hyperbolic space E^ and a nice action of Γ on it. result Finitely generated Veech groups are hierarchically hyperbolic.
Study on geodesic surfaces in hyperbolic 3-orbifolds, proving overlaps in area sets.
problem Understanding overlaps in geometric genus spectra of non-commensurable hyperbolic 3-orbifolds.
method Defined geometric genus spectrum and totally geodesic area set, proving results on overlaps.
result Arithmetic hyperbolic 3-orbifolds can have large overlaps in their totally geodesic area sets.
Study Brownian loops on hyperbolic surfaces, linking to Selberg zeta function.
problem Understanding Brownian loops on hyperbolic surfaces and their relation to Selberg zeta function.
method Computed mass of loops and related to Selberg zeta function for geometrically finite surfaces.
result Relate total loop mass to Selberg zeta function, providing probabilistic interpretations of determinants.
Geometric bounds for low Steklov eigenvalues on hyperbolic surfaces with boundaries.
problem Finding lower bounds for low Steklov eigenvalues of hyperbolic surfaces with geodesic boundaries.
method Analysis of eigenfunction behavior on an adapted thick-thin decomposition for hyperbolic surfaces with geodesic boundaries.
result Sharp geometric lower bounds for low Steklov eigenvalues that depend on the shortest multi-geodesic disconnecting the surfaces.
We define and study the renormalized volume for geometrically finite hyperbolic 3-manifolds, including with rank-1 cusps. We prove a variation formula, and show that for certain families of convex co-compact hyperbolic metrics $g_\eps$ degenerating to a geometrically finite hyperbolic metric g0 with rank-1 cus…
The aim of this survey is to give an overview on the geometry of Einstein maximal globally hyperbolic 2+1 spacetimes of arbitrary curvature, conatining a complete Cauchy surface of finite type. In particular a specialization to the finite type case of the canonicla Wick rotation-rescaling theory, previously developed b…
This article presents some methods to control the bottom of the spectrum of the Laplacian λ0 on hyperbolic surfaces with infinite volume. Our first result bounds the λ0 of a geometrically finite surface in terms of the geometry of its convex core. We then focus on infinite type periodic hyperbolic surfaces built …
Plumbing of surfaces embeds in hyperbolic 4-manifolds.
problem Embedding specific geometric structures in hyperbolic manifolds.
method Using plumbings of disc bundles over surfaces.
result Plumbed structures can be embedded in closed hyperbolic 4-manifolds.
In this paper, we classify completely hyperbolic 3-manifolds corresponding to geometric limits of Kleinian surface groups isomorphic to π1(S) for a finite-type hyperbolic surface S. In the first of the three main theorems, we construct bi-Lipschitz model manifolds for such hyperbolic 3-manifolds, which have a stru…
New group not biautomatic, geometrically constructed.
problem Constructing a non-biautomatic group.
method Using a CAT(0) hierarchically hyperbolic group and geodesic currents.
result First example of a non-biautomatic CAT(0) group of flat-rank 2.
We establish a sharp geometric constant for the upper bound on the resonance counting function for surfaces with hyperbolic ends. An arbitrary metric is allowed within some compact core, and the ends may be of hyperbolic planar, funnel, or cusp type. The constant in the upper bound depends only on the volume of the cor…
We construct first examples of discrete geometrically finite subgroups of PU(2,1) which contain parabolic elements, and are isomorphic to surface groups.
New findings on hyperbolicity of augmented links in thickened surfaces.
problem Proving hyperbolicity of links in thickened surfaces.
method Extending hyperbolicity results to generalized augmented cellular alternating links.
result Generalized augmented cellular alternating links in thickened surfaces are hyperbolic.
Extending BTZ models to complete hyperbolic surfaces.
problem Extending BTZ models to complete hyperbolic surfaces.
method Proving a parametrization result for globally hyperbolic Cauchy-maximal and Cauchy-compact locally Minkowski manifolds with extreme BTZ.
result The tangent bundle of the Teichmüller space parametrizes globally hyperbolic Cauchy-maximal and Cauchy-compact locally Minkowski manifolds with extreme BTZ.
We introduce a new technique for finding CAT(-1) surfaces in hyperbolic 3-manifolds. We use this to show that a complete hyperbolic 3-manifold with finitely generated fundamental group is geometrically and topologically tame.
For hyperbolic Riemann surfaces of finite geometry, we study Selberg's zeta function and its relation to the relative scattering phase and the resonances of the Laplacian. As an application we show that the conjugacy class of a finitely generated, torsion-free, discrete subgroup of SL(2,R) is determined by its trace sp…
The article describes how decorations on hyperbolic surfaces lead to unique tessellations and decompositions.
problem Understanding the geometric structure of decorated hyperbolic surfaces.
method Developing a characterisation of canonical tessellations and dual decompositions using hyperbolic geometry.
result Decorations on hyperbolic surfaces induce unique canonical tessellations and dual decompositions.
The study examines surfaces in hyperbolic 3-manifolds that become nearly flat.
problem Characterizing surfaces in hyperbolic 3-manifolds that become nearly flat.
method Analyzes asymptotically geodesic surfaces in hyperbolic 3-manifolds with finite and infinite volume.
result For finite volume, asymptotically geodesic surfaces are dense; for infinite volume, they do not exist.
The paper finds bounds on shortest dense curves on surfaces.
problem Finding shortest dense curves on surfaces.
method Quantitative density of closed geodesics and orthogeodesics.
result Upper bounds on shortest dense curves.
Paper constructs geometric transitions between hyperbolic and Anti-de Sitter geometries.
problem Transitioning between hyperbolic and Anti-de Sitter geometries.
method Construction via Half-pipe geometry on ΣimesS1 with cone singularities. result Deformation of convex core structure as bending laminations collapse.
New surfaces show horocyclic flow isn't always minimal.
problem Complex dynamics on infinite fineness surfaces.
method Construction of infinite hyperbolic surfaces.
result Horocyclic flow is not minimal on infinite fineness surfaces.
Following on from ``Hyperbolic Plateau problems'' (by the same author), we provide a complete geometric description of solutions to the Plateau problem (S,φ) when S is a compact Riemann surface with a finite number of points removed.
The paper classifies group-actions on surfaces of small genus, focusing on bounding and geometrically bounding cases.
problem Classifying group-actions on surfaces of small genus, particularly focusing on bounding and geometrically bounding cases.
method Analyzing large group-actions on surfaces of genus 3, distinguishing between bounding and geometrically bounding cases.
result Identifies which large group-actions on surfaces of genus 3 are bounding or geometrically bounding.
In this paper the authors study the hyperbolic geometric flow on Riemann surfaces. This new nonlinear geometric evolution equation was recently introduced by the first two authors motivated by Einstein equation and Hamilton's Ricci flow. We prove that, for any given initial metric on R2 in certain class…
Nonorientable hyperbolic surfaces have fewer simple closed geodesics than expected.
problem Understanding the growth of simple closed geodesics on nonorientable hyperbolic surfaces.
method Analyzing the structure of measured laminations and the action of mapping class groups.
result The number of simple closed geodesics is negligible compared to LdimML(S). The theme of this survey is that subgroups of the mapping class group of a finite type surface S can be studied via the geometric/dynamical properties of their action on the Thurston compactification of the Teichmuller space of S, just as discrete subgroups of the isometries of hyperbolic space can be studied via their…
Study continuity of minimal surface areas in hyperbolic 3-manifolds near short geodesics.
problem Understanding the interaction between minimal surfaces and short geodesics in hyperbolic 3-manifolds.
method Geometric convergence of hyperbolic manifolds, lower semi-continuity, continuity of A1. result Lower semi-continuity and continuity of A1 if a minimal surface satisfies certain hypotheses. We prove the convex combination theorem for hyperbolic n-manifolds. Applications are given both in high dimensions and in 3 dimensions. One consequence is that given two geometrically finite subgroups of a discrete group of isometries of hyperbolic n-space, satisfying a natural condition on their parabolic subgroups, t…
New surfaces with special geodesic and horocycle behaviors discovered.
problem Understanding geodesic and horocycle dynamics on hyperbolic surfaces.
method Constructing geometrically infinite hyperbolic surfaces with tailored recurrence properties.
result First examples of non-trivial minimal horocyclic orbit closures and infinite locally-finite conservative horocyclic invariant measures.
The paper generalizes two-field α-attractor models using geometrically finite hyperbolic surfaces.
problem Modeling inflationary dynamics in curved spacetime.
method Coupling four-dimensional gravity to a non-linear sigma model with a hyperbolic scalar manifold.
result Generalized two-field α-attractor models can be parameterized by a surface group and scalar potential.
In this paper we examine the relationship between the length spectrum and the geometric genus spectrum of an arithmetic hyperbolic 3-orbifold M. In particular we analyze the extent to which the geometry of M is determined by the closed geodesics coming from finite area totally geodesic surfaces. Using a variety of tech…
Random walk on hyperbolic surfaces yields uniform distribution of hyperbolic elements.
problem Distribution of lengths in random walks on Fuchsian groups.
method Proof using Gromov's theorem on translation lengths of Gromov-hyperbolic groups.
result Geometric lengths follow laws of large numbers, central limit theorem, etc.
We study the distribution of resonances for geometrically finite hyperbolic surfaces of infinite area by countting resonances numerically. The resonances are computed as zeros of the Selberg zeta function, using an algorithm for computation of the zeta function for Schottky groups. Our particular focus is on three aspe…
We introduce a coarse combinatorial description of the Weil-Petersson distance d_WP(X,Y) between two finite area hyperbolic Riemann surfaces X and Y. The combinatorics reveal a connection between Riemann surfaces and hyperbolic 3-manifolds conjectured by Thurston: the volume of the convex core of the quasi-Fuchsian man…
Geodesic surfaces embed into hyperbolic 3-manifolds for all finite group actions.
problem Embedding geodesic surfaces into hyperbolic 3-manifolds.
method Analyzing finite group actions on surfaces and proving geodesic embeddings for all irreducible cases.
result All quasiplatonic surfaces embed geodesically into hyperbolic 3-manifolds.
Connected flip graphs for triangulations on hyperbolic surfaces.
problem Connecting triangulations on hyperbolic surfaces via flips.
method Proving connectedness of flip graphs and giving bounds on edge flips.
result Flip graphs of geometric triangulations are connected.
No geometric minimal foliations in hyperbolic 3-manifolds.
problem Existence of geometric minimal foliations in hyperbolic three-manifolds.
method Analyzing three-dimensional closed hyperbolic manifolds.
result No locally geometric 1-parameter family of closed minimal surfaces.
The paper constructs complex hyperbolic 2-manifolds with one cusp.
problem Creating complex hyperbolic 2-manifolds with one cusp.
method Explicit geometric construction of smooth projective surfaces and curves.
result Produces one-cusped complex hyperbolic 2-manifolds of arbitrary large volume.
We generalize subset currents on hyperbolic groups to surfaces.
problem Generalizing subset currents to surfaces.
method Developed the theory of subset currents on π_1(Σ), proving they are a measure-theoretic completion of conjugacy classes of subgroups.
result The space of subset currents on Σ is a measure-theoretic completion of conjugacy classes of non-trivial subgroups, each geometrically corresponding to a convex core.
Study horocycle and geodesic orbits on hyperbolic surfaces.
problem Understanding the relationship between horocyclic and geodesic orbits on geometrically infinite surfaces.
method Analyzing the topological dynamics of the horocycle flow on hyperbolic surfaces, focusing on specific vectors and their orbits.
result The closure of the horocycle flow of a non-periodic vector intersects geodesic orbits along an unbounded sequence of points.
Finite area surfaces have cyclic hyperbolic Veech groups.
problem Understanding Veech groups of flat surfaces with finite area.
method Analyzing specific flat surfaces to find cyclic hyperbolic Veech groups.
result Finite area surfaces can have Veech groups that are infinite cyclic and hyperbolic.
We study arc graphs and curve graphs for surfaces of infinite topological type. First, we define an arc graph relative to a finite number of (isolated) punctures and prove that it is a connected, uniformly hyperbolic graph of infinite diameter; this extends a recent result of J. Bavard to a large class of punctured sur…
The paper investigates the distribution of systoles on arithmetic Riemann surfaces.
problem Understanding the asymptotic behavior of systoles on arithmetic Riemann surfaces.
method Combining combinatorics, group theory, and geometric group theory.
result The set of arithmetic surfaces cannot be concentrated, indicating the same for systoles.
Algorithm morphs graphs on hyperbolic surfaces.
problem Morphing graphs on hyperbolic surfaces.
method Generalization of Tutte's spring embedding theorem.
result First algorithm for morphing graphs on hyperbolic surfaces.
A finite-volume hyperbolic 3-manifold geometrically bounds if it is the geodesic boundary of a finite-volume hyperbolic 4-manifold. We construct here an example of non-compact, finite-volume hyperbolic 3-manifold that geometrically bounds. The 3-manifold is the complement of a link with eight components, and its volume…