Rubin's theorem

Rubin's theorem, originating from the field of set theory, addresses the conditions under which certain mathematical statements can be true or false in a model of set theory. It typically concerns properties of cardinalities (sizes of sets) and posits that if certain statements hold true in one set-theoretical universe, they will also hold in others. Essentially, it helps mathematicians understand the stability of mathematical truths across different frameworks, providing a bridge between abstract set theory and more concrete mathematical concepts.