In set theory, a branch of mathematics, the Milner – Rado paradox, found by Eric Charles Milner and Richard Rado, states that every ordinal number α {\displaystyle \alpha } less than the successor κ + {\displaystyle \kappa ^{+}} of some cardinal number κ {\displaystyle \kappa } can be written as the union of sets X 1, X 2, . .. Wikipedia