English
Related papers

Related papers: Characterizations of Some Parity Signed Graphs

200 papers

This article provides structural characterization of simple graphs whose edge-set can be partitioned into maximum matchings. We use Vizing's classification of simple graphs based on edge chromatic index.

Combinatorics · Mathematics 2012-10-19 Niraj Khare

Given a connected graph, the principal eigenvector of the adjacency matrix (often called the Perron vector) can be used to assign positive weights to the vertices. A natural way to measure the homogeneousness of this vector is by…

Combinatorics · Mathematics 2026-03-26 Péter Csikvári , Viktor Harangi

Two competing types of interactions often play an important part in shaping system behavior, such as activatory or inhibitory functions in biological systems. Hence, signed networks, where each connection can be either positive or negative,…

Social and Information Networks · Computer Science 2024-01-09 Yu Tian , Renaud Lambiotte

A half-square of a bipartite graph $B=(X,Y,E_B)$ has one color class of $B$ as vertex set, say $X$; two vertices are adjacent whenever they have a common neighbor in $Y$. If $G=(V,E_G)$ is the half-square of a planar bipartite graph…

Discrete Mathematics · Computer Science 2018-12-12 Hoang-Oanh Le , Van Bang Le

In this paper, we show that every connected signed graph with smallest eigenvalue strictly greater than $-2$ and large enough minimum degree is switching equivalent to a complete graph. This is a signed analogue of a theorem of Hoffman. The…

Combinatorics · Mathematics 2021-04-06 Alexander L. Gavrilyuk , Akihiro Munemasa , Yoshio Sano , Tetsuji Taniguchi

Betweenness centrality is a centrality measure based on the overall amount of shortest paths passing through a given vertex. A graph is betweenness-uniform if all its vertices have the same betweenness centrality. We study the properties of…

Combinatorics · Mathematics 2023-09-11 David Hartman , Aneta Pokorná , Pavel Valtr

Let G be a simple balanced bipartite graph on $2n$ vertices, $\delta = \delta(G)/n$, and $\rho={\delta + \sqrt{2 \delta -1} \over 2}$. If $\delta > 1/2$ then it has a $\lfloor \rho n \rfloor$-regular spanning subgraph. The statement is…

Combinatorics · Mathematics 2007-10-13 Béla Csaba

A signed graph is a graph where the edges are assigned labels of either "$+$" or "$-$". The sign of a cycle in the graph is the product of the signs of its edges. We equip each signed complete graph with a vector whose entries are the…

Combinatorics · Mathematics 2017-07-03 Alex Schaefer

An isometric path between two vertices in a graph $G$ is a shortest path joining them. The isometric path number of $G$, denoted by $\ip(G)$, is the minimum number of isometric paths needed to cover all vertices of $G$. In this paper, we…

Combinatorics · Mathematics 2007-05-23 Jun-Jie Pan , Gerard J. Chang

We prove that every graph of rank-width $k$ is a pivot-minor of a graph of tree-width at most $2k$. We also prove that graphs of rank-width at most 1, equivalently distance-hereditary graphs, are exactly vertex-minors of trees, and graphs…

Combinatorics · Mathematics 2014-03-26 O-joung Kwon , Sang-il Oum

There are many concepts of signed graph coloring which are defined by assigning colors to the vertices of the graphs. These concepts usually differ in the number of self-inverse colors used. We introduce a unifying concept for this kind of…

Combinatorics · Mathematics 2022-11-07 Chiara Cappello , Eckhard Steffen

We study additively graceful labelings of signed graphs on stars and double stars. While the case of signed stars is straightforward, the problem becomes significantly more intricate for signed double stars. We obtain a characterization of…

Combinatorics · Mathematics 2026-04-24 Brian DSouza , Jessica Pereira

The parameter $\sigma(G)$ of a graph $G$ stands for the number of Laplacian eigenvalues greater than or equal to the average degree of $G$. In this work, we address the problem of characterizing those graphs $G$ having $\sigma(G)=1$. Our…

The spectral properties of signed directed graphs, which may be naturally obtained by assigning a sign to each edge of a directed graph, have received substantially less attention than those of their undirected and/or unsigned counterparts.…

Combinatorics · Mathematics 2021-10-12 Pepijn Wissing , Edwin R. van Dam

For a finite simple graph $G$, say $G$ is of dimension $n$, and write $\dim(G) = n$, if $n$ is the smallest integer such that $G$ can be represented as a unit-distance graph in $\mathbb{R}^n$. Define $G$ to be \emph{dimension-critical} if…

Combinatorics · Mathematics 2023-03-30 Matt Noble

We consider signed graphs, i.e, graphs with positive or negative signs on their edges. We determine the admissible parameters for the $\{5,6,\ldots,10\}$-regular signed graphs which have only two distinct eigenvalues. For each obtained…

Combinatorics · Mathematics 2019-09-17 Farzaneh Ramezani

Given a connected graph $G$, the metric (resp. edge metric) dimension of $G$ is the cardinality of the smallest ordered set of vertices that uniquely identifies every pair of distinct vertices (resp. edges) of $G$ by means of distance…

Combinatorics · Mathematics 2020-06-23 Martin Knor , Snjezana Majstorovic , Aoden Teo Masa Toshi , Riste Skrekovski , Ismael G. Yero

A split graph is a graph whose vertices can be partitioned into a clique and a stable set. We investigate the combinatorial species of split graphs, providing species-theoretic generalizations of enumerative results due to B\'ina and…

Combinatorics · Mathematics 2019-07-16 Justin M. Troyka

For a graph $G$ and $a,b\in V(G)$, the shortest path reconfiguration graph of $G$ with respect to $a$ and $b$ is denoted by $S(G,a,b)$. The vertex set of $S(G,a,b)$ is the set of all shortest paths between $a$ and $b$ in $G$. Two vertices…

Combinatorics · Mathematics 2017-05-29 John Asplund , Kossi Edoh , Ruth Haas , Yulia Hristova , Beth Novick , Brett Werner

A near-factor of a finite simple graph $G$ is a matching that saturates all vertices except one. A graph $G$ is said to be near-factor-critical if the deletion of any vertex from $G$ results in a subgraph that has a near-factor. We prove…

Combinatorics · Mathematics 2014-05-19 Kuo-Ching Huang , Ko-Wei Lih