The Complexity of Homomorphisms of Signed Graphs and Signed Constraint Satisfaction

@inproceedings{Foucaud2014TheCO,
  title={The Complexity of Homomorphisms of Signed Graphs and Signed Constraint Satisfaction},
  author={Florent Foucaud and Reza Naserasr},
  booktitle={LATIN},
  year={2014}
}
A signed graph (G, Σ) is an undirected graph G together with an assignment of signs (positive or negative) to all its edges, where Σ denotes the set of negative edges. Two signatures are said to be equivalent if one can be obtained from the other by a sequence of resignings (i.e. switching the sign of all edges incident to a given vertex). Extending the notion of usual graph homomorphisms, homomorphisms of signed graphs were introduced, and have lead to some extensions and strengthenings in the… 

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