Ramsey theory over partitions II: Negative Ramsey relations and pump-up theorems

Abstract

In this series of papers we advance Ramsey theory over partitions. In this part, we concentrate on anti-Ramsey relations, or, as they are better known, strong colorings, and in particular solve two problems from [CKS21].

It is shown that for every infinite cardinal λ, a strong coloring on λ⁺ by λ colors over a partition can be stretched to one with λ⁺ colors over the same partition. Also, a sufficient condition is given for when a strong coloring witnessing Pr₁(…) over a partition may be improved to witness Pr₀(…).

Since the classical theory corresponds to the special case of a partition with just one cell, the two results generalize pump-up theorems due to Eisworth and Shelah, respectively.