Abstract

Suppose that α = γ + δ where $\gamma \geq \delta > 0$ . Then there is a graph G = (ω ω α ,E) which has no independent set of order type ω ω α and has no pentagram (a pentagram is a set of five points with all pairs joined by edges). In the notation of Erdos and Rado, who generalized Ramsey's Theorem to this setting, $\omega^{\omega^\alpha} \nrightarrow (\omega^{\omega^\alpha},5)^2.$