A blue-empty graph is an extremal graph in which the forced triangles are all the same color. Call the number of red monochromatic
forced triangles and
the number of blue monochromatic
forced triangles, then a blue-empty graph is an extremal
graph with
.
For even
, a blue-empty graph can be achieved by coloring red two complete subgraphs of
points (the red net method).
There is no blue-empty coloring for odd
except for
(Lorden 1962).
Blue-Empty Graph
See also
Complete Graph, Extremal Graph, Monochromatic Forced Triangle, Red NetExplore with Wolfram|Alpha
References
Lorden, G. "Blue-Empty Chromatic Graphs." Amer. Math. Monthly 69, 114-120, 1962.Sauvé, L. "On Chromatic Graphs." Amer. Math. Monthly 68, 107-111, 1961.Referenced on Wolfram|Alpha
Blue-Empty GraphCite this as:
Weisstein, Eric W. "Blue-Empty Graph." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Blue-EmptyGraph.html