Follow

New blog post: Triply-Hamiltonian edge colorings

https://11011110.github.io/blog/2018/12/02/triply-hamiltonian-edge.html

In https://mathstodon.xyz/@mjd/101098853869827835, Mark Jason Dominus (@mjd) observed that the regular dodecahedron can have its edges properly colored with three colors so that every two colors form a Hamiltonian cycle. In this post, I survey constructions for more graphs like this, and prove that no planar bipartite graph can have a coloring like this.

I have protanopia, which is one of the kinds of colourblindness commonly called 'red-green'.

Using different colours makes sense, since it's a colouring problem, but getting even three colours that are good for everyone is tricky. Different patterns is the safest way to go, as you've done.

@christianp @mjd Better now?

Christian Lawson-Perfect@christianp@mathstodon.xyz@11011110 @mjd that three-colouring sounds interesting, but I can only see two colours in the first diagram of your post. Are two of the colours red and green? The thick blue/yellow/black in the second diagram is easier to see, for me.