Tag Archives: coloring

Four color theorem: what next?


The algorithm I use to color graphs works pretty well … BUT: Sometimes (very rarely) it gets into an infinite loop where also random Kempe color switches (around the entire graph) do NOT work. The good is, if I reprocess … Continue reading

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Four color theorem: Infinite switches are not enough :-( :-(


A new edge 12-7 that connects the edges 6-10 and 32-15. With this case seems that infinite random switches throughout the entire graph do not solve the impasse, which is really really really bad.

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Four color theorem: Tait edge coloring video


And here is the video that shows how to get a Tait colored map (graph) from a rectangular map.

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Four color theorem: Tait edge coloring


From Wikipedia: “The four color theorem, on vertex coloring of planar graphs, is equivalent to the statement that every bridgeless 3-regular planar graph is of class one (Tait 1880). This statement is now known to be true, due to the … Continue reading

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