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Directed graphs can be studied by their associated directed flag complex. The homology of this complex has been successful in applications as a topological invariant for digraphs. Through comparison with path homology theory, we derive a…

Algebraic Topology · Mathematics 2024-11-08 Thomas Chaplin , Heather A. Harrington , Ulrike Tillmann

We introduce a filtration on the simplicial homology of a finite simplicial complex X using bi-colourings of its vertices. This yields two dual homology theories closely related to discrete Morse matchings on X. We give an explicit…

Combinatorics · Mathematics 2022-12-05 Daniele Celoria

Persistent homology of the Rips filtration allows to track topological features of a point cloud over scales, and is a foundational tool of topological data analysis. Unfortunately, the Rips-filtration is exponentially sized, when…

Computational Geometry · Computer Science 2018-07-27 Bernhard Brehm , Hanne Hardering

We prove that every finite connected simplicial complex has the homology of the classifying space for some $\mathrm{CAT}(0)$ cubical duality group. More specifically, for any finite simplicial complex $X$, we construct a locally…

Metric Geometry · Mathematics 2012-12-11 Raeyong Kim

A simplicial complex is a generalization of a graph: a collection of n-ary relationships (instead of binary as the edges of a graph), named simplices. In this paper, we develop a new tool to study the structure of simplicial complexes: we…

Social and Information Networks · Computer Science 2021-02-16 Giulia Preti , Gianmarco De Francisci Morales , Francesco Bonchi

For a compact oriented smooth $n$-manifold $M$ and a codimension-$1$ homology class $\phi \in \operatorname{H}_{n-1}(M, \partial M)$, we investigate a simplicial complex $\mathcal{S}^\dagger(M, \phi)$ relating the properly embedded…

Geometric Topology · Mathematics 2022-02-23 Gerrit Herrmann , José Pedro Quintanilha

The paper surveys recent progress in understanding geometric, topological and combinatorial properties of large simplicial complexes, focusing mainly on ampleness, connectivity and universality. In the first part of the paper we concentrate…

Combinatorics · Mathematics 2023-01-19 Michael Farber

We provide first a categorical exploration of, and then completion of the mapping of the relationships among, three fundamental perspectives on binary relations: as the incidence matrices of hypergraphs, as the formal contexts of concept…

Combinatorics · Mathematics 2025-04-22 Robert E. Green , Cliff A. Joslyn , Audun Myers , Michael G. Rawson , Michael Robinson

We present a new computing package Flagser, designed to construct the directed flag complex of a finite directed graph, and compute persistent homology for flexibly defined filtrations on the graph and the resulting complex. The persistent…

Algebraic Topology · Mathematics 2019-06-26 Daniel Luetgehetmann , Dejan Govc , Jason Smith , Ran Levi

In this paper we consider the dg-category of twisted complexes over simplicial ringed spaces. It is clear that a simplicial map $f: (\mathcal{U},\mathcal{R})\to (\mathcal{V}, \mathcal{S})$ between simplicial ringed spaces induces a…

Category Theory · Mathematics 2021-05-31 Zhaoting Wei

A central problem in topological data analysis is that of computing the homology of a given simplicial complex. Said complexes can have arbitrary large number of simplices, as can happen, for example, if the space is the Rips-Vietoris or…

Combinatorics · Mathematics 2021-11-11 Francisco Martinez-Figueroa

The purpose of this note is to point out that simplicial methods and the well-known Dold-Kan construction in simplicial homotopy theory can be fruitfully applied to convert link homology theories into homotopy theories. Dold and Kan prove…

Algebraic Topology · Mathematics 2017-09-22 Louis H Kauffman

Proximity complexes and filtrations are central constructions in topological data analysis. Built using distance functions, or more generally metrics, they are often used to infer connectivity information from point clouds. Here we…

Computational Geometry · Computer Science 2021-06-07 Gabriele Beltramo , Primoz Skraba

A flag complex can be defined as a simplicial complex whose simplices correspond to complete subgraphs of its 1-skeleton taken as a graph. In this article, by introducing the notion of s-dismantlability, we shall define the s-homotopy type…

Combinatorics · Mathematics 2019-06-04 Romain Boulet , Etienne Fieux , Bertrand Jouve

Given a sample $Y$ from an unknown manifold $X$ embedded in Euclidean space, it is possible to recover the homology groups of $X$ by building a Vietoris--Rips or \v{C}ech simplicial complex on top of the vertex set $Y$. However, these…

Metric Geometry · Mathematics 2019-11-28 Henry Adams , Joshua Mirth

Given a metric space $(X,d)$, the Vietoris-Rips complex of $X$ at a scale of $r >0$ is a simplicial complex whose simplices are all those finite subsets of $X$ with diameter less than $r$. In this paper, we classify, up to simplicial…

Combinatorics · Mathematics 2025-08-25 Vinay Sipani , Ramesh Kasilingam

Topological spaces, represented by simplicial complexes, capture richer relationships than graphs by modeling interactions not only between nodes but also among higher-order entities, such as edges or triangles. This motivates the…

Machine Learning · Statistics 2025-04-09 Chengen Liu , Victor M. Tenorio , Antonio G. Marques , Elvin Isufi

There is a canonical way to associate two simplicial complexes K, L to any relation $R\subset X\times Y$. Moreover, the geometric realizations of K and L are homotopy equivalent. This was studied in the fifties by C.H. Dowker. In this…

Combinatorics · Mathematics 2007-05-23 Elias Gabriel Minian

Given a point cloud $P$ in Euclidean space and a positive parameter $t$ we can consider the $t$-neighborhood $P^{t}$ of $P$ consisting of points at distance less than $t$ to $P$. Homology of $P^{t}$ gives information about components,…

Algebraic Topology · Mathematics 2019-04-25 Nello Blaser , Morten Brun

A Rado simplicial complex X is a generalisation of the well-known Rado graph. X is a countable simplicial complex which contains any countable simplicial complex as its induced subcomplex. The Rado simplicial complex is highly symmetric, it…

Combinatorics · Mathematics 2020-01-31 Michael Farber , Lewis Mead , Lewin Strauss