Homomorphisms of Signed Graphs

@article{Naserasr2015HomomorphismsOS,
  title={Homomorphisms of Signed Graphs},
  author={Reza Naserasr and Edita Rollov{\'a} and {\'E}ric Sopena},
  journal={Journal of Graph Theory},
  year={2015},
  volume={79}
}
A signed graph [G,Σ] is a graph G together with an assignment of signs + and − to all the edges of G where Σ is the set of negative edges. Furthermore [G,Σ1] and [G,Σ2] are considered to be equivalent if the symmetric difference of Σ1 and Σ2 is an edge cut of G. Naturally arising from matroid theory, several notions of graph theory, such as the theory of minors and the theory of nowhere‐zero flows, have been already extended to signed graphs. In an unpublished manuscript, B. Guenin introduced… 

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