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In this paper, we construct a comparison map from the topological fundamental group to the pro-\'etale fundamental group for a complex variety.

Algebraic Geometry · Mathematics 2023-08-17 Jiu-Kang Yu , Lei Zhang

Higher Homotopy van Kampen Theorems allow the computation as colimits of certain homotopical invariants of glued spaces. One corollary is to describe homotopical excision in critical dimensions in terms of induced modules and crossed…

Algebraic Topology · Mathematics 2013-10-15 Ronald Brown , Rafael Sivera

The fundamental groupoid of a locally 0 and 1-connected space classifies covering spaces, or equivalently local systems. When the space is topologically stratified Treumann, based on unpublished ideas of MacPherson, constructed an `exit…

Algebraic Topology · Mathematics 2013-09-16 Jonathan Woolf

We develop a homotopy theory of directed graphs based on cubical homotopy groups, also referred to as A-groups or reduced GLMY homotopy groups. Localizing the category of directed graphs at morphisms that induce isomorphisms on these groups…

Algebraic Topology · Mathematics 2026-05-07 Briony Eldridge , Sergei O. Ivanov , Xiaomeng Xu , Shing-Tung Yau , Mengmeng Zhang

Using tools from the theory of Lie groupoids, we study the category of logarithmic flat connections on principal $G$-bundles, where $G$ is a complex reductive structure group. Flat connections on the affine line with a logarithmic…

Differential Geometry · Mathematics 2020-10-09 Francis Bischoff

Using an algebraic point of view we present an introduction to the groupoid theory, that is, we give fundamental properties of groupoids as, uniqueness of inverses and properties of the identities, and study subgroupoids, wide subgroupoids…

Group Theory · Mathematics 2020-01-29 Jesús Ávila , Víctor Marín , Héctor Pinedo

We describe various path homology theories constructed for a directed hypergraph. We introduce the category of directed hypergraphs and the notion of a homotopy in this category. Also, we investigate the functoriality and the homotopy…

Algebraic Topology · Mathematics 2021-09-22 Yuri Muranov , Anna Szczepkowska , Vladimir Vershinin

We introduce and study, for a process P delivering edges on the Cartesian product of the vertex sets of a given set of graphs, the P-product of these graphs, thereby generalizing many types of product graph. Analogous to the notion of a…

Combinatorics · Mathematics 2017-02-10 Izak Broere , Johannes Heidema

We establish rigidity theorems for graph product von Neumann algebras $M_\Gamma=*_{v,\Gamma}M_v$ associated to finite simple graphs $\Gamma$ and families of tracial von Neumann algebras $(M_v)_{v\in\Gamma}$. We consider the following three…

Operator Algebras · Mathematics 2025-09-09 Camille Horbez , Adrian Ioana

We study the question of polytopality of graphs: when is a given graph the graph of a polytope? We first review the known necessary conditions for a graph to be polytopal, and we provide several families of graphs which satisfy all these…

Metric Geometry · Mathematics 2013-04-30 Julian Pfeifle , Vincent Pilaud , Francisco Santos

Directed Algebraic Topology is beginning to emerge from various applications. The basic structure we shall use for such a theory, a 'd-space', is a topological space equipped with a family of 'directed paths', closed under some operations.…

Algebraic Topology · Mathematics 2007-05-23 Marco Grandis

In this paper, we will show dichotomy theorems for the computation of polynomials corresponding to evaluation of graph homomorphisms in Valiant's model. We are given a fixed graph $H$ and want to find all graphs, from some graph class,…

Computational Complexity · Computer Science 2014-12-02 Christian Engels

We study graph products of groups from the viewpoint of measured group theory. We first establish a full measure equivalence classification of graph products of countably infinite groups over finite simple graphs with no transvection and no…

Group Theory · Mathematics 2024-01-10 Amandine Escalier , Camille Horbez

In this paper we construct two groupoids from morphisms of groupoids, with one from a categorical viewpoint and the other from a geometric viewpoint. We show that for each pair of groupoids, the two kinds of groupoids of morphisms are…

Category Theory · Mathematics 2019-08-16 Bohui Chen , Cheng-Yong Du , Rui Wang

This paper gives an extension of the classical Zariski-van Kampen theorem describing the fundamental groups of the complements of plane singular curves by generators and relations. It provides a procedure for computation of the first…

Algebraic Geometry · Mathematics 2007-05-23 D. Chéniot , A. Libgober

We upgrade the classical operation of \textit{isomonodromic deformations} along a path $\gamma$ to a functor $\mathbb{P}_{\gamma}$ between categories of flat connections with logarithmic singularities along a divisor $D$, which itself…

Algebraic Geometry · Mathematics 2025-12-08 Waleed Qaisar

We focus on the algorithm underlying the main result of [A. Mestre, R. Oeckl, Generating loop graphs via Hopf algebra in quantum field theory. J. Math. Phys., 47, 122302, 2006]. This is an algebraic formula to generate all connected graphs…

Combinatorics · Mathematics 2013-03-14 Angela Mestre

Let $p$ be an odd prime. From a simple undirected graph $G$, through the classical procedures of Baer (Trans. Am. Math. Soc., 1938), Tutte (J. Lond. Math. Soc., 1947) and Lov\'asz (B. Braz. Math. Soc., 1989), there is a $p$-group $P_G$ of…

Combinatorics · Mathematics 2020-05-05 Xiaoyu He , Youming Qiao

We follow the same technics we used before in \cite{AZ} of extending knot Floer homology to embedded graphs in a 3-manifold, by using the Kauffman topological invariant of embedded graphs by associating family of links and knots to a such…

Algebraic Topology · Mathematics 2018-01-08 Ahmad Zainy Al-Yasry

Thomason's Homotopy Colimit Theorem has been extended to bicategories and this extension can be adapted, through the delooping principle, to a corresponding theorem for diagrams of monoidal categories. In this version, we show that the…

Category Theory · Mathematics 2011-03-24 A. R. Garzón , R. Pérez