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arXiv · 1906.05638

On the 4-color theorem for signed graphs

František Kardoš·Jonathan Narboni
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Abstract

There are several ways to generalize graph coloring to signed graphs. Máčajová, Raspaud and Škoviera introduced one of them and conjectured that in this setting, for signed planar graphs four colors are always enough, generalising thereby The Four Color Theorem. We disprove the conjecture.

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František Kardoš, Jonathan Narboni. 2019-06-13. On the 4-color theorem for signed graphs. https://arxiv.org/abs/1906.05638

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