Mathematician Disproves Hedetniemi’s Graph Theory Conjecture
I've heard vaguely of the coloring problems before, but this one quote is confusing me, can someone explain what I'm missing?<p>> Even the question that launched the field — Do four colors suffice to color any map? — took more than a century to answer (the answer is yes, in case you were wondering).<p>But what if my "map" includes a node that has more than four neighbors?  If there are only four colors, then one of the neighbors must be pidgeon-holed to share a color with the node?  Are there constraints on how many neighbors a node can have?