Was Ulam right? I: Basic theory and subnormal ideals

Abstract

We introduce various colouring principles which generalise the so-called onto mapping principle of Sierpiński to larger cardinals and general ideals. We prove that these principles capture the notion of an Ulam matrix and allow to characterise large cardinals, most notably weakly compact and ineffable cardinals. We also develop the basic theory of these colouring principles, connecting them to the classical negative square bracket partition relations, proving pumping-up theorems, and deciding various instances of theirs. We also demonstrate that our principles provide a uniform way of obtaining non-saturation results for ideals satisfying a property we call subnormality in contexts where Ulam matrices might not be available.