- 15,456 hits
- 3-edge coloring 4 4 color theorem 4ct Alfred Bray Kempe algorithm Brendan McKay Cahit spiral chains color coloring coloring maps colour cubic graphs different edge embedding Euler four Four color four color music four color problem four colors suffice four color theorem Francis Guthrie Fullerene graph graph coloring Graph isomorphism graphs representations Graph theory Gunnar Brinkmann Hamilton homeomorphic impasse isomorphic graphs Java Kempe Kempe chain Kenneth Appel map new features oeis pencil and paper plantri problem proof proper colorings sage sagemath tait Tait coloring theorem tutte Wolfgang Haken
stefanutti on Quotes Todd Gibson on Quotes G.A. on Four color theorem: new i… Four color theorem:… on Four color theorem: back to th… Question about 3-reg… on Four color theorem: simplified… G.A. on Abstract Four color theorem:… on Four color theorem: counterexa… stefanutti on Four color theorem: representa… Guy on Four color theorem: representa… Brian Gordon on Four color theorem: 3-edge col…
Some rights reserved. Read here.
Tag Archives: tait
This post follows directly the previous one. I’m down to a single case to prove (pag. 3). I think I should move to Java coding, implementing the entire algorithm: map reduction (removing edges), color reduced map, restore of edges one at a … Continue reading
Finally I bought two books about the four color theorem: “Four Colors Suffice: How the Map Problem Was Solved” by Robin Wilson e Ian Stewart; and the “The Four-Color Theorem: History, Topological Foundations, and Idea of Proof” by Rudolf Fritsch and Gerda Fritsch. I’am in … Continue reading
It is known that for regular maps, “3-edge coloring” is equivalent to finding a proper “four coloring” of the faces of a map. This post is about coloring impasses, fallacious Kempe chain color swapping (not solving the impasse) and an hypothesis I’d … Continue reading
😦 Too many more things to do and little time: Filter out duplicates. I finally found a java library to efficiently filter out all isomorphic graphs. It is a library part if the sspace project. Using it I will be able … Continue reading
And here is the video that shows how to get a Tait colored map (graph) from a rectangular map.