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The cut-rank of a set $X$ in a graph $G$ is the rank of the $X\times (V(G)-X)$ submatrix of the adjacency matrix over the binary field. A split is a partition of the vertex set into two sets $(X,Y)$ such that the cut-rank of $X$ is less…

Combinatorics · Mathematics 2022-11-30 Sang-il Oum

The intersection graph of ideals associated with a commutative unitary ring $R$ is the graph $G(R)$ whose vertices all non-trivial ideals of $R$ and there exists an edge between distinct vertices if and only if the intersection of them is…

Combinatorics · Mathematics 2023-09-26 E. Dodongeh , A. Moussavi , R. Nikandish

A vertex-colored graph $G$ is said to be rainbow vertex-connected if every two vertices of $G$ are connected by a path whose internal vertices have distinct colors, such a path is called a rainbow path. The rainbow vertex-connection number…

Combinatorics · Mathematics 2012-01-10 Xueliang Li , Yaping Mao , Yongtang Shi

The {\it Randi\'c index} $R(G)$ of a graph $G$ is defined as the sum of 1/\sqrt{d_ud_v} over all edges $uv$ of $G$, where $d_u$ and $d_v$ are the degrees of vertices $u$ and $v,$ respectively. Let $D(G)$ be the diameter of $G$ when $G$ is…

Combinatorics · Mathematics 2011-04-05 Yiting Yang , Linyuan Lu

A graph is a structure composed of a set of vertices (i.e.nodes, dots) connected to one another by a set of edges (i.e.links, lines). The concept of a graph has been around since the late 19$^\text{th}$ century, however, only in recent…

Data Structures and Algorithms · Computer Science 2010-12-24 Marko A. Rodriguez , Peter Neubauer

A simple graph $G=(V,E)$ on $n$ vertices is said to be recursively partitionable (RP) if $G \simeq K_1$, or if $G$ is connected and satisfies the following recursive property: for every integer partition $a_1, a_2, \dots, a_k$ of $n$, there…

Combinatorics · Mathematics 2022-10-20 Calum Buchanan , Brandon Du Preez , K. E. Perry , Puck Rombach

A directed graph $G=(V,E)$ is twinless strongly connected if it contains a strongly connected spanning subgraph without any pair of antiparallel (or twin) edges. The twinless strongly connected components (TSCCs) of a directed graph $G$ are…

Data Structures and Algorithms · Computer Science 2020-09-23 Loukas Georgiadis , Evangelos Kosinas

We define the $k$-cut complex of a graph $G$ with vertex set $V(G)$ to be the simplicial complex whose facets are the complements of sets of size $k$ in $V(G)$ inducing disconnected subgraphs of $G$. This generalizes the Alexander dual of a…

Let $R$ be a finite product of integral domains and $D$ be a union of prime ideals (it is possible that $R$ is just an integral domain). Let $n \geq 1$ be a positive integer. This paper introduces the $n$-total graph of a $(R, D)$. The…

Commutative Algebra · Mathematics 2026-01-19 Myriam AbiHabib , Ayman Badawi

We show that if a graph $G$ satisfies certain conditions then the connectivity of neighbourhood complex $\mathcal{N}(G)$ is strictly less than the vertex connectivity of $G$. As an application, we give a relation between the connectivity of…

Combinatorics · Mathematics 2023-04-27 Rekha Santhanam , Samir Shukla

Integrated Gradients (IG) is a common explainability technique to address the black-box problem of neural networks. Integrated gradients assumes continuous data. Graphs are discrete structures making IG ill-suited to graphs. In this work,…

Machine Learning · Computer Science 2025-09-10 Lachlan Simpson , Kyle Millar , Adriel Cheng , Cheng-Chew Lim , Hong Gunn Chew

The weak minor G of a graph G is the graph obtained from G by a sequence of edge-contraction operations on G. A weak-minor-closed family of upper embeddable graphs is a set G of upper embeddable graphs that for each graph G in G, every weak…

Combinatorics · Mathematics 2012-03-06 Guanghua Dong , Ning Wang , Yuanqiu Huang , Han Ren , Yanpei Liu

Consider a graph $\Gamma$. A set $ S $ of vertices in $\Gamma$ is called a {cyclic vertex cutset} of $\Gamma$ if $\Gamma - S$ is disconnected and has at least two components containing cycles. If $\Gamma$ has a cyclic vertex cutset, then it…

Combinatorics · Mathematics 2025-04-02 Ramesh Prasad Panda

Let $G=(V,E)$ be a simple undirected graph with $n$ vertices then a set partition $\pi=\{V_1, ..., V_k\}$ of the vertex set of $G$ is a connected set partition if each subgraph $G[V_j]$ induced by the blocks $V_j$ of $\pi$ is connected for…

Combinatorics · Mathematics 2015-03-17 Frank Simon , Peter Tittmann , Martin Trinks

The strong geodetic problem on a graph $G$ is to determine a smallest set of vertices such that by fixing one shortest path between each pair of its vertices, all vertices of $G$ are covered. To do this as efficiently as possible, strong…

Combinatorics · Mathematics 2018-04-02 Valentin Gledel , Vesna Iršič , Sandi Klavžar

We prove a structure theorem for stable functions on amenable groups, which extends the arithmetic regularity lemma for stable subsets of finite groups. Given a group $G$, a function $f\colon G\to [-1,1]$ is called stable if the binary…

Logic · Mathematics 2024-06-18 Gabriel Conant , Anand Pillay

In this article, we propose a new type of square matrix associated with an undirected graph by trading off the naturally imbedded symmetry in them. The proposed matrix is defined using the neighbourhood sets of the vertices. It is called as…

Discrete Mathematics · Computer Science 2019-03-14 Sivakumar Karunakaran , Lavanya Selvaganesh

Let \Delta be a finite building (or, more generally, a thick spherical and locally finite building). The chamber graph G(\Delta), whose edges are the pairs of adjacent chambers in \Delta, is known to be q-regular for a certain number…

Combinatorics · Mathematics 2012-07-24 Anders Björner , Kathrin Vorwerk

Let $G$ be a graph, and let $w$ be a positive real-valued weight function on $V(G)$. For every subset $S$ of $V(G)$, let $w(S)=\sum_{v \in S} w(v).$ A non-empty subset $S \subset V(G)$ is a weighted safe set of $(G,w)$ if, for every…

Combinatorics · Mathematics 2020-02-25 Shinya Fujita , Tadashi Sakuma , Boram Park

Recent work at the intersection of formal language theory and graph theory has explored graph grammars for graph modeling. However, existing models and formalisms can only operate on homogeneous (i.e., untyped or unattributed) graphs. We…

Social and Information Networks · Computer Science 2023-01-06 Satyaki Sikdar , Neil Shah , Tim Weninger