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We prove an asymptotic formula for the Euler characteristic of Kontsevich's commutative graph complex. This formula implies that the total amount of commutative graph homology grows super-exponentially with the rank and, via a theorem of…

Algebraic Topology · Mathematics 2024-08-20 Michael Borinsky , Don Zagier

Graph homomorphism has been studied intensively. Given an m x m symmetric matrix A, the graph homomorphism function is defined as \[Z_A (G) = \sum_{f:V->[m]} \prod_{(u,v)\in E} A_{f(u),f(v)}, \] where G = (V,E) is any undirected graph. The…

Computational Complexity · Computer Science 2011-10-10 Jin-Yi Cai , Xi Chen , Pinyan Lu

Graded skew-commutative rings occur often in practice. Here are two examples: 1) The cohomology ring of a compact three-dimensional manifold. 2) The cohomology ring of the complement of a hyperplane arrangement (the Orlik-Solomon algebra).…

Rings and Algebras · Mathematics 2010-05-18 Jan-Erik Roos

This paper continues the investigation of the configuration space of two distinct points on a graph. We analyze the process of adding an additional edge to the graph and the resulting changes in the topology of the configuration space. We…

Algebraic Topology · Mathematics 2015-03-17 Michael Farber , Elizabeth Hanbury

The Hom complex ${\rm Hom}(T,G)$ of graphs is a CW-complex associated to a pair of graphs $T$ and $G$, considered in the graph coloring problem. It is known that certain homotopy invariants of ${\rm Hom}(T,G)$ give lower bounds for the…

Combinatorics · Mathematics 2017-08-01 Takahiro Matsushita

We prove that the existence of a positively defined, invariant Einstein metric $m$ on a connected homogeneous space $G/H$ of a compact Lie group $G$ is the consequence of non-contractibility of some compact set $C=X_{G,H}^{\Sigma}$ (B\"ohm…

Differential Geometry · Mathematics 2013-05-23 Michail M. Graev

We survey some of the known results on the relation between the homology of the {\em full} Hecke algebra of a reductive $p$-adic group $G$, and the representation theory of $G$. Let us denote by $\CIc(G)$ the full Hecke algebra of $G$ and…

K-Theory and Homology · Mathematics 2007-05-23 Victor Nistor

Let $R$ be a ring with unity. The \emph{idempotent graph} $G_{\text{Id}}(R)$ of a ring $R$ is an undirected simple graph whose vertices are the set of all the elements of ring $R$ and two vertices $x$ and $y$ are adjacent if and only if…

Combinatorics · Mathematics 2023-06-16 Praveen Mathil , Barkha Baloda , Jitender Kumar

The paper systematically classifies rings based on the dominant metric dimensions (Ddim) of their associated CZDG, establishing consequential bounds for the Ddim of these compressed zero-divisor graphs. The authors investigate the interplay…

Commutative Algebra · Mathematics 2024-05-09 Nasir Ali , Hafiz Muhammad Afzal Siddiqui , Muhammad Imran Qureshi

We study homological invariants of the Steinberg algebra $\mathcal{A}_k(\mathcal{G})$ of an ample groupoid $\mathcal{G}$ over a commutative ring $k$. For $\mathcal{G}$ principal or Hausdorff with…

K-Theory and Homology · Mathematics 2025-05-29 Guido Arnone , Guillermo Cortiñas , Devarshi Mukherjee

Let $G$ be a finite simple connected graph on $[n]$ and $R = K[x_1, \ldots, x_n]$ the polynomial ring in $n$ variables over a field $K$. The edge ideal of $G$ is the ideal $I(G)$ of $R$ which is generated by those monomials $x_ix_j$ for…

Commutative Algebra · Mathematics 2020-08-13 Takayuki Hibi , Hiroju Kanno , Kyouko Kimura , Kazunori Matsuda , Adam Van Tuyl

We develop new techniques for the construction and classification of representations of row-finite and locally convex higher-rank graph C*-algebras O. This class includes Cuntz--Krieger algebras associated to row-finite directed graphs. Our…

Operator Algebras · Mathematics 2026-04-20 Arnaud Brothier , Aidan Sims , Dilshan Wijesena

Let $G$ be a graph with adjacency matrix $A(G)$ and degree matrix $D(G)$, and let $L_\mu(G):=A(G)-\mu D(G)$. Two graphs $G_1$ and $G_2$ are called \emph{degree-similar} if there exists an invertible matrix $M$ such that $M^{-1} A(G_1) M…

Combinatorics · Mathematics 2025-09-03 Yi-Zheng Fan , Ruo-Jie Xing , Yi-Liu Zhang , Wei Wang

For a finite point set $E\subset \mathbb{R}^d$ and a connected graph $G$ on $k+1$ vertices, we define a $G$-framework to be a collection of $k + 1$ points in E such that the distance between a pair of points is specified if the…

Combinatorics · Mathematics 2018-05-22 A. Iosevich , J. Passant

An $(m, n)$-colored-mixed graph $G=(V, A_1, A_2,\cdots, A_m, E_1, E_2,\cdots, E_n)$ is a graph having $m$ colors of arcs and $n$ colors of edges. We do not allow two arcs or edges to have the same endpoints. A homomorphism from an…

Combinatorics · Mathematics 2020-09-01 Fabien Jacques , Pascal Ochem

For any graph $G=(V,E)$, a subset $S\subseteq V$ \emph{dominates} $G$ if all vertices are contained in the closed neighborhood of $S$, that is $N[S]=V$. The minimum cardinality over all such $S$ is called the domination number, written…

Combinatorics · Mathematics 2016-04-06 Aziz Contractor , Elliot Krop

Standard combinatorial construction, due to Kontsevich, associates to any $\ai$-algebra with an invariant inner product, an inhomogeneous class in the cohomology of the moduli spaces of Riemann surfaces with marked points. We propose an…

Algebraic Topology · Mathematics 2008-01-08 Alastair Hamilton , Andrey Lazarev

$Hom(G,H)$ is a polyhedral complex defined for any two undirected graphs $G$ and $H$. This construction was introduced by Lov\'asz to give lower bounds for chromatic numbers of graphs. In this paper we initiate the study of the topological…

Combinatorics · Mathematics 2007-05-23 Eric Babson , Dmitry N. Kozlov

The algebra of truncated polynomials A_m=Z[x]/(x^m) plays an important role in the theory of Khovanov and Khovanov-Rozansky homology of links. We have demonstrated that Hochschild homology is closely related to Khovanov homology via…

Geometric Topology · Mathematics 2007-05-23 Milena D. Pabiniak , Jozef H. Przytycki , Radmila Sazdanovic

For almost any compact connected Lie group $G$ and any field $\mathbb{F}\_p$, we compute the Batalin-Vilkoviskyalgebra $H^{*+\text{dim }G}(LBG;\mathbb{F}\_p)$ on the loop cohomology of the classifying space introduced byChataur and the…

Algebraic Topology · Mathematics 2016-10-14 Katsuhiko Kuribayashi , Luc Menichi
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