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Let E(1)_K denote the closed 4-manifold that is homotopy equivalent (hence homeomorphic) to the rational elliptic surface E(1) and is obtained by performing Fintushel-Stern knot surgery on E(1) using a knot K in S^3. We construct an…

Geometric Topology · Mathematics 2007-05-23 Tolga Etgü , B. Doug Park

These notes provide an introduction to Giroux's theory of convex surfaces in contact 3-manifolds and its simplest applications. They put a special emphasis on pictures and discussions of explicit examples. The first goal is to explain why…

Geometric Topology · Mathematics 2013-03-06 Patrick Massot

We provide an algorithm to solve the word problem in all fundamental groups of closed 3-manifolds; in particular, we show that these groups are autostackable. This provides a common framework for a solution to the word problem in any closed…

Group Theory · Mathematics 2017-12-14 Mark Brittenham , Susan Hermiller , Tim Susse

We show that a Kleinian surface group, or hyperbolic 3-manifold with a cusp-preserving homotopy-equivalence to a surface, has bounded geometry if and only if there is an upper bound on an associated collection of coefficients that depend…

Geometric Topology · Mathematics 2009-11-07 Yair N. Minsky

Existing research highlights the crucial role of topological priors in image segmentation, particularly in preserving essential structures such as connectivity and genus. Accurately capturing these topological features often requires…

Computer Vision and Pattern Recognition · Computer Science 2026-01-19 Wenxiao Li , Xue-Cheng Tai , Jun Liu

A real 3-manifold is a smooth 3-manifold together with an orientation preserving smooth involution, which is called a real structure. A real contact 3-manifold is a real 3-manifold with a contact distribution that is antisymmetric with…

Geometric Topology · Mathematics 2023-05-08 Merve Cengiz , Ferit Öztürk

About a decade ago Thurston proved that a vast collection of 3-manifolds carry metrics of constant negative curvature. These manifolds are thus elements of {\em hyperbolic geometry}, as natural as Euclid's regular polyhedra. For a closed…

Geometric Topology · Mathematics 2016-09-06 Curt McMullen

In dynamic tomography the object undergoes changes while projections are being acquired sequentially in time. The resulting inconsistent set of projections cannot be used directly to reconstruct an object corresponding to a time instant.…

Image and Video Processing · Electrical Eng. & Systems 2024-01-30 Berk Iskender , Marc L. Klasky , Yoram Bresler

This paper presents a method for improved analysis of objects with an axial symmetry using X-ray Computed Tomography (CT). Cylindrical coordinates about an axis fixed to the object form the most natural base to check certain characteristics…

Image and Video Processing · Electrical Eng. & Systems 2020-10-06 Wannes Goethals , Marjolein Heyndrickx , Matthieu Boone

Motivated by geometry processing for surfaces with non-trivial topology, we study discrete harmonic maps between closed surfaces of genus at least two. Harmonic maps provide a natural framework for comparing surfaces by minimizing…

Numerical Analysis · Mathematics 2025-09-03 Zhipeng Zhu , Wai Yeung Lam , Lok Ming Lui

For a closed Riemannian manifold $\mathcal{M}$ and a metric space $S$ with a small Gromov$\unicode{x2013}$Hausdorff distance to it, Latschev's theorem guarantees the existence of a sufficiently small scale $\beta>0$ at which the…

Algebraic Topology · Mathematics 2024-03-25 Sushovan Majhi

We continue our exploration of the extent to which the spectrum encodes the local geometry of a locally homogeneous three-manifold and find that if $(M,g)$ and $(N,h)$ are a pair of locally homogeneous, locally non-isometric isospectral…

Differential Geometry · Mathematics 2019-11-01 Samuel Lin , Benjamin Schmidt , Craig Sutton

Selective Rips complexes corresponding to a sequence of parameters are a generalization of Vietoris-Rips complexes utilizing the idea of thin simplices. We prove that if a metric space $Y$ is close (in Gromov-Hausdorff distance) to a closed…

Algebraic Topology · Mathematics 2023-04-21 Boštjan Lemež , Žiga Virk

We study geodesically complete and locally compact Hadamard spaces X whose Tits boundary is a connected irreducible spherical building. We show that X is symmetric iff complete geodesics in X do not branch and a Euclidean building…

Metric Geometry · Mathematics 2009-03-04 Bernhard Leeb

We will describe some results regarding the algorithmic nature of homeomorphism problems for manifolds; in particular, the following theorem. Theorem 1: Every PL or smooth simply connected manifold M^n of dimension n at least 5 can be…

Geometric Topology · Mathematics 2016-09-07 Alexander Nabutovsky , Shmuel Weinberger

This paper presents an approach that reconstructs a hand-held object from a monocular video. In contrast to many recent methods that directly predict object geometry by a trained network, the proposed approach does not require any learned…

Computer Vision and Pattern Recognition · Computer Science 2022-12-01 Di Huang , Xiaopeng Ji , Xingyi He , Jiaming Sun , Tong He , Qing Shuai , Wanli Ouyang , Xiaowei Zhou

Using the idea of the degree of a smooth mapping between two manifolds of the same dimension we present here the topological (homotopical) classification of the mappings between spheres of the same dimension, vector fields, monopole and…

Mathematical Physics · Physics 2011-04-28 Jerzy Szczesny , Marek Biesiada , Marek Szydlowski

In this thesis we construct 3-parameter families $G(p,q,r)$ of embedded arcs with fixed boundary in a 4-manifold. We then analyze these elements of $\pi_3\mathsf{Emb}_\partial(I,M)$ using embedding calculus by studying the induced map from…

Geometric Topology · Mathematics 2025-11-05 Shruthi Sridhar-Shapiro

Let $G$ be a group of homeomorphisms of a topological space $X$. $G$ is $\textit{(properly) isometrizable}$ if there exists a $G$-invariant (proper) gauge structure on $X$. $G$ is $\textit{equiregular}$ if for every $x \in X$ and every open…

General Topology · Mathematics 2021-05-19 Fredric D. Ancel

We establish Gromov's celebrated reconstruction theorem in Lorentzian geometry. Alongside this result, we introduce and study a natural concept of isomorphy of normalized bounded Lorentzian metric measure spaces. We outline applications to…

Differential Geometry · Mathematics 2025-06-13 Mathias Braun , Clemens Sämann