"The Ramsey number R(m,n) gives the solution to the party problem,
which asks the minimum number of guests R(m,n) that must be invited so
that at least m will know each other or at least n will not know each
other. In the language of graph theory, the Ramsey number is the
minimum number of vertices such that all undirected simple graphs of
order v contain a clique of order m or an independent set of order n.
Ramsey's theorem states that such a number exists for all m and n".