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We construct a correspondence between epimorphisms $\varphi \colon \pi_1(M) \to F_r$ from the fundamental group of a compact manifold $M$ onto the free group of rank $r$, and systems of $r$ framed non-separating hypersurfaces in $M$, which…

Geometric Topology · Mathematics 2025-05-29 Wacław Marzantowicz , Łukasz Patryk Michalak

Random geometric graphs are random graph models defined on metric spaces. Such a model is defined by first sampling points from a metric space and then connecting each pair of sampled points with probability that depends on their distance,…

Machine Learning · Computer Science 2026-04-10 Han Huang , Pakawut Jiradilok , Elchanan Mossel

We define a notion of Morse function and establish Morse theory-like theorems over offsets of any compact set in a Euclidean space at regular values of their distance function. Using non-smooth analysis and tools from geometric measure…

Geometric Topology · Mathematics 2025-07-28 Antoine Commaret

For a topological space $X$ we study continuous maps $f : X\to \mathbb R^m$ such that images of every pairwise distinct $k$ points are affinely (linearly) independent. Such maps are called affinely (linearly) $k$-regular embeddings. We…

Algebraic Topology · Mathematics 2011-06-29 R. N. Karasev

Despite high-dimensionality of images, the sets of images of 3D objects have long been hypothesized to form low-dimensional manifolds. What is the nature of such manifolds? How do they differ across objects and object classes? Answering…

Computer Vision and Pattern Recognition · Computer Science 2025-03-11 Benjamin Beaudett , Shenyuan Liang , Anuj Srivastava

We present a new technique that enables manifold learning to accurately embed data manifolds that contain holes, without discarding any topological information. Manifold learning aims to embed high dimensional data into a lower dimensional…

Robotics · Computer Science 2022-03-11 Thomas Cohn , Nikhil Devraj , Odest Chadwicke Jenkins

Topological surgery occurs in natural phenomena where two points are selected and attracting or repelling forces are applied. The two points are connected via an invisible `thread'. In order to model topologically such phenomena we…

Geometric Topology · Mathematics 2018-09-24 Sofia Lambropoulou , Stathis Antoniou , Nikola Samardzija

This is a paper in a series that studies smooth relative Lie algebra homologies and cohomologies based on the theory of formal manifolds and formal Lie groups. In three previous papers, we introduce the notion of formal manifolds and study…

Differential Geometry · Mathematics 2025-01-22 Fulin Chen , Binyong Sun , Chuyun Wang

We directly connect topological changes that can occur in mathematical three-space via surgery, with black hole formation, the formation of wormholes and new generalizations of these phenomena. This work widens the bridge between topology…

Geometric Topology · Mathematics 2018-12-20 Stathis Antoniou , Louis H. Kauffman , Sofia Lambropoulou

We discuss a problem on singularity theory of differentiable (smooth) or real algebraic maps which is different from knowing existence and has been difficult: constructing explcit real algebraic functions. We discuss construction of real…

Algebraic Geometry · Mathematics 2025-06-24 Naoki Kitazawa

The Reeb space of a continuous function is the space of connected components of the level sets. In this paper we first prove that the Reeb space of a smooth function on a closed manifold with finitely many critical values has the structure…

Geometric Topology · Mathematics 2020-06-03 Osamu Saeki

We relate general maps to bipartite maps through a bijection of type slit-slide-sew. We provide an involution on arbitrary genus maps with even degree faces. This enables a full interpretation of the relation between general and bipartite…

Combinatorics · Mathematics 2026-04-23 Jérémie Bettinelli , Dimitri Korkotashvili

A Reeb graph is a graphical representation of a scalar function on a topological space that encodes the topology of the level sets. A Reeb space is a generalization of the Reeb graph to a multiparameter function. In this paper, we propose…

Computational Geometry · Computer Science 2024-10-17 Qingsong Wang , Guanqun Ma , Raghavendra Sridharamurthy , Bei Wang

In our previous work, we have constructed explicit smooth real algebraic functions which may have both compact and non-compact preimages on smooth real algebraic manifolds. This paper presents its variant. Our result is new in obtaining…

Algebraic Geometry · Mathematics 2023-05-25 Naoki Kitazawa

Starting from Borel's description of the mod-2 cohomology of real flag manifolds, we give a minimal presentation of the cohomology ring for semi complete flag manifolds $F_{k,m}:=F(1,\ldots,1,m)$ where $1$ is repeated $k$ times. The…

Algebraic Topology · Mathematics 2015-11-19 Jesús González , Barbara Gutiérrez , Darwin Gutiérrez , Adriana Lara

Comparing invariants from both topological and geometric perspectives is a key focus in index theorem. This paper compares higher analytic and topological torsions and establishes a version of the higher Cheeger-M\"uller/Bismut-Zhang…

Differential Geometry · Mathematics 2026-02-04 Martin Puchol , Junrong Yan

By a Morse function on a compact manifold with boundary we mean a real-valued function without critical points near the boundary such that its critical points as well as the critical points of its restriction to the boundary are all…

Geometric Topology · Mathematics 2019-05-15 Dominik Wrazidlo

Random walks on spaces with hyperbolic properties tend to sublinearly track geodesic rays which point in certain hyperbolic-like directions. Qing-Rafi-Tiozzo recently introduced the sublinearly Morse boundary and proved that this boundary…

Geometric Topology · Mathematics 2022-07-15 Matthew Gentry Durham , Abdul Zalloum

We study the topological construction called Mapper in the context of simply connected domains, in particular on images. The Mapper construction can be considered as a generalization for contour, split, and joint trees on simply connected…

Computer Vision and Pattern Recognition · Computer Science 2017-12-11 Alejandro Robles , Mustafa Hajij , Paul Rosen

Browder-Novikov-Sullivan-Wall surgery theory investigates the homotopy types of manifolds, using a combination of algebra and topology. It is the aim of these notes to provide an introduction to the more algebraic aspects of the theory…

Algebraic Topology · Mathematics 2007-05-23 Andrew Ranicki