In the paper *Partition theorems for systems of finite subsets of integers*, Pudlák and Rödl show a Ramsey-type result. The main feature of this result is that the sizes of sets in such systems are not fixed in advance (as in Ramsey's original theorem and Erdős and Rado's generalization to arbitrary partitions of $[\mathbb{N}]^k$).

The proof of the main theorem is by induction on $\omega_1$, and the authors say that the idea of doing that came from an unpublished manuscript by Ketonen, *Set theory for a small universe, I. The Paris-Harrington Axiom.*
Does anyone here has access to this manuscript?

Thanks in advance.

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