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I propose that most problems about circles (cycles, circuits) in ordinary graphs that have odd or even length find their proper setting in the theory of signed graphs, where each edge has a sign, $+$ or $-$. Even-circle and odd-circle…

Combinatorics · Mathematics 2021-06-21 Thomas Zaslavsky

We examine the conditions under which a signed graph contains an edge or a vertex that is contained in a unique negative circle or a unique positive circle. For an edge in a unique signed circle, the positive and negative case require the…

Combinatorics · Mathematics 2017-01-03 Richard Behr

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

A signed graph is a graph together with an assignment of signs to the edges. A closed walk in a signed graph is said to be positive (negative) if it has an even (odd) number of negative edges, counting repetition. Recognizing the signs of…

Combinatorics · Mathematics 2021-06-16 Reza Naserasr , Eric Sopena , Thomas Zaslavsky

A signed graph is a graph whose edges are signed. In a vertex-signed graph the vertices are signed. The latter is called consistent if the product of signs in every circle is positive. The line graph of a signed graph is naturally…

Combinatorics · Mathematics 2021-06-21 Thomas Zaslavsky

A "signed graph" is a graph $\Gamma$ where the edges are assigned sign labels, either "$+$" or "$-$". The sign of a cycle is the product of the signs of its edges. Let $\mathrm{SpecC}(\Gamma)$ denote the list of lengths of cycles in…

Combinatorics · Mathematics 2021-06-21 Alex Schaefer , Thomas Zaslavsky

Signed graphs are graphs with signed edges. They are commonly used to represent positive and negative relationships in social networks. While balance theory and clusterizable graphs deal with signed graphs to represent social interactions,…

Discrete Mathematics · Computer Science 2014-05-21 Anne-Marie Kermarrec , Christopher Thraves

Signed graphs are graphs whose edges get a sign $+1$ or $-1$ (the signature). Signed graphs can be studied by means of graph matrices extended to signed graphs in a natural way. Recently, the spectra of signed graphs have attracted much…

Combinatorics · Mathematics 2019-07-11 Francesco Belardo , Sebastian M. Cioabă , Jack H. Koolen , Jianfeng Wang

Clustering a signed graph means partitioning the vertices into sets ("clusters") so that every positive edge, and no negative edge, is within a cluster. Clustering is not always possible; the obstruction is circles with exactly one negative…

Combinatorics · Mathematics 2024-05-07 Michael G. Gottstein , Leila Parsaei-Majd , Thomas Zaslavsky

Signed graphs have their edges labeled either as positive or negative. Here we introduce two types of signed distance matrix for signed graphs. We characterize balance in signed graphs using these matrices and we obtain explicit formulae…

Combinatorics · Mathematics 2021-06-21 Shahul Hameed K , Shijin T , Soorya P , Germina K A , Thomas Zaslavsky

A signed graph is a graph $G$ associated with a mapping $\sigma: E(G)\to \{-1,+1\}$, denoted by $(G,\sigma)$. A $cycle$ of $(G,\sigma)$ is a connected 2-regular subgraph. A cycle $C$ is $positive$ if it has an even number of negative edges,…

Combinatorics · Mathematics 2018-03-09 Yezhou Wu , Dong Ye

A signed graph is a graph whose edges are labeled positive or negative. The sign of a cycle is the product of the signs of its edges. Zaslavsky proved in 2012 that, up to switching isomorphism, there are six different signed Petersen…

Combinatorics · Mathematics 2021-10-12 Deepak Sehrawat , Bikash Bhattacharjya

A signed graph is an ordered pair $\Sigma=(G,\sigma),$ where $G=(V,E)$ is the underlying graph of $\Sigma$ with a signature function $\sigma:E\rightarrow \{1,-1\}$. In this article, we define $n^{th}$ power of a signed graph and discuss…

Combinatorics · Mathematics 2020-09-23 Shijin T , Germina K A , Shahul Hameed K

A signed graph is a graph in which each edge has a positive or negative sign. In this article, first we characterize the distance compatibility in the case of a connected signed graph and discussed the distance compatibility criterion for…

Combinatorics · Mathematics 2020-09-21 T. V. Shijin , P. Soorya , K. Shahul Hameed , K. A. Germina

A signed graph is a graph whose edges are labeled either positive or negative. Corresponding to the two signed distance matrices defined for signed graphs, we define two signed distance laplacian matrices. We characterize balance in signed…

Combinatorics · Mathematics 2020-10-12 Roshni T Roy , K A Germina , K Shahul Hameed , Thomas Zaslavsky

In a signed graph each edge has a sign, $+1$ or $-1$. We introduce in the present paper a new definition of connection in a signed graph by the existence of both positive and negative chains between vertices. We prove some results and…

Combinatorics · Mathematics 2017-08-08 Ouahiba Bessouf , Abdelkader Khelladi , Thomas Zaslavsky

The line graph of a graph with signed edges carries vertex signs. A vertex-signed graph is consistent if every circle (cycle, circuit) has positive vertex-sign product. Acharya, Acharya, and Sinha recently characterized line-consistent…

Combinatorics · Mathematics 2021-06-21 Daniel C. Slilaty , Thomas Zaslavsky

A signed graph is a graph with a function that assigns a label of positive or negative to each edge. The sign of a circle is the product of the signs of its edges; a graph is balanced if all of its circles are positive. A set of edges whose…

Combinatorics · Mathematics 2020-10-07 Nicholas Lacasse

A signed graph is a graph with edges marked positive and negative; it is unbalanced if some cycle has negative sign product. We introduce the concept of vector valued switching function in signed graphs, which extends the concept of…

Combinatorics · Mathematics 2023-05-23 Shahul Hameed K , Albin Mathew , Germina K A , Thomas Zaslavsky

A signed graph is one that features two types of edges: positive and negative. Balanced signed graphs are those in which all cycles contain an even number of positive edges. In the adjacency matrix of a signed graph, entries can be $0$,…

Combinatorics · Mathematics 2024-08-15 Cristian M. Conde , Ezequiel Dratman , Luciano N. Grippo
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