blue-empty coloring

An extremal graph in which the forced triangles are all the same color. Call R the number of red monochromatic forced triangles and B the number of blue monochromatic forced triangles, then a blue-empty graph is an extremal graph with B = 0. For even n, a blue-empty graph can be achieved by coloring red two complete subgraphs of n/2 points (the red net method). There is no blue-empty coloring for odd n except for n = 7.

complete graph | extremal graph | monochromatic forced triangle | red net