Results 61 to 70 of about 2,598,126 (331)
On Cartesian Products of Signed Graphs [PDF]
Discrete Applied Mathematics, 2020 In this paper, we study the Cartesian product of signed graphs as defined by Germina, Hameed and Zaslavsky (2011). Here we focus on its algebraic properties and look at the chromatic number of some Cartesian products. One of our main results is the unicity of the prime factor decomposition of signed graphs.
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Eigenspaces for \(-2\) in signed line graphs
The American Journal of CombinatoricsIt is known that \(-2\) appears in the spectrum of a connected signed line graph if and only if its root is either (a) a balanced signed graph, not a tree, that spans a switching of the complete signed graph or (b) an unbalanced simply signed graph ...
Zoran Stanić
doaj +1 more source
Consistency in the Naturally Vertex-Signed Line Graph of a Signed Graph [PDF]
Bulletin of the Malaysian Mathematical Sciences Society, 2015 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 vertex-signed. Based on a characterization by Acharya, Acharya, and Sinha in 2009, we give constructions for the signed ...
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The Chromatic Number of a Signed Graph [PDF]
The Electronic Journal of Combinatorics, 2016 In 1982, Zaslavsky introduced the concept of a proper vertex colouring of a signed graph $G$ as a mapping $\phi\colon V(G)\to \mathbb{Z}$ such that for any two adjacent vertices $u$ and $v$ the colour $\phi(u)$ is different from the colour $\sigma(uv)\phi(v)$, where is $\sigma(uv)$ is the sign of the edge $uv$.
Martin Škoviera +2 more
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Homomorphisms of signed graphs: An update
European Journal of Combinatorics, 2021 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 closed walks as one of the key structural properties of a signed graph, we define a homomorphism of a signed graph $
Naserasr, Reza +2 more
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Some Properties of the Eigenvalues of the Net Laplacian Matrix of a Signed Graph
Discussiones Mathematicae Graph Theory, 2020 Given a signed graph Ġ, let AĠ and DG˙± D_{\dot G}^ \pm denote its standard adjacency matrix and the diagonal matrix of vertex net-degrees, respectively.
Z. Stanić
semanticscholar +1 more source
Polarity-based graph neural network for sign prediction in signed bipartite graphs
World wide web (Bussum), 2022 As a fundamental data structure, graphs are ubiquitous in various applications. Among all types of graphs, signed bipartite graphs contain complex structures with positive and negative links as well as bipartite settings, on which conventional graph ...
Xianhang Zhang +5 more
semanticscholar +1 more source
Projective-planar signed graphs and tangled signed graphs
Journal of Combinatorial Theory, Series B, 2007 AbstractA projective-planar signed graph has no two vertex-disjoint negative circles. We prove that every signed graph with no two vertex-disjoint negative circles and no balancing vertex is obtained by taking a projective-planar signed graph or a copy of −K5 and then taking 1-, 2-, and 3-sums with balanced signed graphs.
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Social context prevents heat hormetic effects against mutagens during fish development
FEBS Letters, EarlyView.This study shows that sublethal heat stress protects fish embryos against ultraviolet radiation, a concept known as ‘hormesis’. However, chemical stress transmission between fish embryos negates this protective effect. By providing evidence for the mechanistic molecular basis of heat stress hormesis and interindividual stress communication, this study ...
Lauric Feugere +5 more
wiley +1 more source
Molecular Oncology, EarlyView.Cancer‐associated fibroblasts (CAFs) promote cancer growth, invasion (metastasis), and drug resistance. Here, we identified functional and diverse circulating CAFs (cCAFs) in patients with metastatic prostate cancer (mPCa). cCAFs were found in higher numbers and were functional and diverse in mPCa patients versus healthy individuals, suggesting their ...
Richell Booijink +6 more
wiley +1 more source