The r-colour Ramsey number Rr(k) is the minimum n∈ℕ such that
every r-colouring of the edges of the complete graph Kn on n
vertices contains a monochromatic copy of Kk. We prove, for each
fixed r≥2, that
Rr(k)≤e−δkrrk
for some constant δ=δ(r)>0 and...