Ramsey Multiplicities of Graphs with Five Vertices

The Ramsey multiplicity \( M(G) \) of a graph \( G \) is defined to be the smallest number of monochromatic copies of \( G \) in any two-coloring of edges of \( K_{R(G)} \), where \( R(G) \) is the smallest integer \( n \) such that every graph on \( n \) vertices either contains \( G \) or its complement contains \( G \). With the help of computer algorithms, we obtain the exact values of Ramsey multiplicities for most of isolate-free graphs on five vertices, and establish upper bounds for a few others.