Ramsey's theorem is a theorem about coloring. You want to color the edges of a complete graph on n vertices with k different colors. The theorem says (among oth

Ramsey's theorem is a theorem about coloring. You want to color the edges of a complete graph on n vertices with k different colors. The theorem says (among other things) that you can't color the edges of the complete graph with six vertices with just two colors without creating a monochromatic triangle.