Parameterized partition relations on the real numbers

Abstract

We consider several kinds of partition relations on the set \({\mathbb{R}}\) of real numbers and its powers, as well as their parameterizations with the set \({[\mathbb{N}]^{\mathbb{N}}}\) of all infinite sets of natural numbers, and show that they hold in some models of set theory. The proofs use generic absoluteness, that is, absoluteness under the required forcing extensions. We show that Solovay models are absolute under those forcing extensions, which yields, for instance, that in these models for every well ordered partition of \({\mathbb{R}^\mathbb{N}}\) there is a sequence of perfect sets whose product lies in one piece of the partition. Moreover, for every finite partition of \({[\mathbb{N}]^{\mathbb{N}} \times \mathbb{R}^{\mathbb{N}}}\) there is \({X \in [\mathbb{N}]^{\mathbb{N}}}\) and a sequence \({\{P_{k} : k \in \mathbb{N}\}}\) of perfect sets such that the product \({[X]^{\mathbb{N}} \times \prod_{k}^{\infty}P_{k}}\) lies in one piece of the partition, where \({[X]^{\mathbb{N}}}\) is the set of all infinite subsets of X. The proofs yield the same results for Borel partitions in ZFC, and for more complex partitions in any model satisfying a certain degree of generic absoluteness.