18. Large cardinals

{α < κ : f α (β) = 0} and {α < κ : f α (β) = 1} is in U, so we can let ε(β) ∈ 2 be such that
{α < κ : f α (β) = ε(β)} ∈ U. Then
⋂
{α < κ : f α (β) = ε(β)} ∈ U;
β