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It is conjectured that every cusped hyperbolic 3-manifold admits a geometric triangulation, i.e. it is decomposed into positive volume ideal hyperbolic tetrahedra. Here, we show that sufficiently highly twisted knots admit a geometric…

Geometric Topology · Mathematics 2023-06-14 Sophie L. Ham , Jessica S. Purcell

We bound from above the expected total Betti number of a high degree random real hypersurface in a smooth real projective manifold. This upper bound is deduced from the equirepartition of critical points of a real Lefschetz pencil…

Algebraic Geometry · Mathematics 2011-07-13 Damien Gayet , Jean-Yves Welschinger

We classify the complete hyperbolic 3-manifolds admitting a maximal cusp of volume at most 2.62. We use this to show that the figure-8 knot complement is the unique 1-cusped hyperbolic 3-manifold with nine or more non-hyperbolic fillings;…

Geometric Topology · Mathematics 2021-09-30 David Gabai , Robert Haraway , Robert Meyerhoff , Nathaniel Thurston , Andrew Yarmola

The isometry group of a compact n-dimensional hyperbolic manifold is known to be finite. We show that for every n > 2, every finite group is realized as the full isometry group of some compact hyperbolic n-manifold. The cases n = 2 and n =…

Group Theory · Mathematics 2009-11-10 M. Belolipetsky , A. Lubotzky

We prove that for any oriented cusped hyperbolic 3-manifold $M$ and any compact oriented 3-manifold $N$ with tori boundary, there exists a finite cover $M'$ of $M$ that admits a degree-8 map $f:M'\to N$, i.e. $M$ virtually 8-dominates $N$.

Geometric Topology · Mathematics 2025-07-02 Hongbin Sun

We find upper and lower bounds for the first eigenvalue and the volume entropy of a noncompact real analytic K\"ahler manifold, in terms of Calabi's diastasis function and diastatic entropy, which are sharp in the case of the complex…

Differential Geometry · Mathematics 2015-02-04 Roberto Mossa

It is well-known that random groups with at least as many relators as generators have vanishing first betti number with high probability. In this paper we extend this question and study maps from few-relators random groups to infinite…

Group Theory · Mathematics 2019-02-19 Gareth Wilkes

In this paper we show that bending a finite volume hyperbolic $d$-manifold $M$ along a totally geodesic hypersurface $\Sigma$ results in a properly convex projective structure on $M$ with finite volume. We also discuss various geometric…

Geometric Topology · Mathematics 2020-04-10 Samuel A. Ballas , Ludovic Marquis

We show that for any integers k and g, with g at least two, there are infinitely many closed hyperbolic 3-manifolds which are integral homology spheres with Casson invariant k, and Heegaard genus equal to g. This existence result is shown…

Geometric Topology · Mathematics 2014-05-27 Alexander Lubotzky , Joseph Maher , Conan Wu

A 3-manifold is Haken if it contains a topologically essential surface. The Virtual Haken Conjecture says that every irreducible 3-manifold with infinite fundamental group has a finite cover which is Haken. Here, we discuss two interrelated…

Geometric Topology · Mathematics 2014-11-11 Nathan M Dunfield , William P Thurston

In this paper we develop the theory of finite-type invariants for homologically nontrivial 3-manifolds. We construct an infinite-dimensional affine space with a hypersurface in it corresponding to manifolds with Morse singularities.…

q-alg · Mathematics 2008-02-03 Nadya Shirokova

In this paper we obtain new upper bounds on volumes of right-angled polyhedra in hyperbolic space $\mathbb{H}^3$ in three different cases: for ideal polyhedra with all vertices on the ideal hyperbolic boundary, for compact polytopes with…

Geometric Topology · Mathematics 2022-01-06 Stepan Alexandrov , Nikolay Bogachev , Andrei Egorov , Andrei Vesnin

In this paper, we find lower bounds for volumes of hyperbolic 3-manifolds with various topological conditions. Let V_3 = 1.01494 denote the volume of a regular ideal simplex in hyperbolic 3-space. As a special case of the main theorem, if a…

Geometric Topology · Mathematics 2007-05-23 Ian Agol

In this paper, we introduce a particularly nice family of locally CAT(-1) spaces, which we call hyperbolic P-manifolds. For $X^3$ a simple, thick hyperbolic P-manifold of dimension 3, we show that certain subsets of the boundary at infinity…

Group Theory · Mathematics 2007-05-23 J. -F. Lafont

In this article we show that given a Salem number $\lambda$, a totally real number field $k\subseteq\mathbb{Q}(\lambda+\lambda^{-1})$, and a positive integer $n\geq\mathrm{deg}_k(\lambda)-1$, there exist infinitely many commensurability…

Geometric Topology · Mathematics 2026-02-09 Michelle Chu , Plinio G. P. Murillo

The first $\ell^2$ Betti number of a group is non-decreasing under various embeddings arising from first order logic. Strict inequality is proved for elementary embeddings of non-abelian proper subgroups within torsion free hyperbolic…

Group Theory · Mathematics 2026-05-21 Connor MacMahon

We count the number of conjugacy classes of maximal, genus g, surface subroups in hyperbolic 3-manifold groups. For any closed hyperbolic 3-manifold, we show that there is an upper bound on this number which grows factorially with g. We…

Geometric Topology · Mathematics 2014-10-01 Joseph D. Masters

We present a short elementary proof of an existence theorem of certain CAT(-1)-surfaces in open hyperbolic 3-manifolds. The main construction lemma in Calegari and Gabai's proof of Marden's Tameness Conjecture can be replaced by an…

Geometric Topology · Mathematics 2009-03-03 Teruhiko Soma

For each integer $n \geq 3$, we exhibit a nonuniform arithmetic lattice in $\mathrm{SO}(n,1)$ containing Zariski-dense surface subgroups.

Group Theory · Mathematics 2022-07-20 Sami Douba

Let M be a compact oriented irreducible 3-manifold which is neither a graph manifold nor a hyperbolic manifold. We prove that the fundamental group of M is virtually special.

Group Theory · Mathematics 2013-07-25 Piotr Przytycki , Daniel T. Wise