Countable chain condition in partition calculus Original Research Article

A new kind of partition calculus is exposed. As an application we prove a partition relation which strengthens the well-known relations ω1 → ((α,ω1),(α)k)2 of K. Prikry (1972) and ω1 → (α)k2 of J. Baumgartner and A. Hajnal (1973).