On "finitary" Ramsey's theorem

Abstract

We examine a version of Ramsey's theorem based on Tao, Gaspar and Kohlenbach's "finitary" infinite pigeonhole principle.We will show that the "finitary" infinite Ramsey's theorem naturally gives rise to statements at the level of the infinite Ramsey's theorem, Friedman's infinite adjacent Ramsey theorem (well-foundedness of certain ordinals up to $\varepsilon_0$), $1$-consistency of theories up to PA and the finite Ramsey's theorem.