Metamath Proof Explorer


Theorem fiufl

Description: A finite set satisfies the ultrafilter lemma. (Contributed by Mario Carneiro, 26-Aug-2015)

Ref Expression
Assertion fiufl ⊢ X ∈ Fin → X ∈ UFL

Proof

Step Hyp Ref Expression
1 pwfi ⊢ X ∈ Fin ↔ 𝒫 X ∈ Fin
2 pwfi ⊢ 𝒫 X ∈ Fin ↔ 𝒫 𝒫 X ∈ Fin
3 finnum ⊢ 𝒫 𝒫 X ∈ Fin → 𝒫 𝒫 X ∈ dom ⁡ card
4 numufl ⊢ 𝒫 𝒫 X ∈ dom ⁡ card → X ∈ UFL
5 3 4 syl ⊢ 𝒫 𝒫 X ∈ Fin → X ∈ UFL
6 2 5 sylbi ⊢ 𝒫 X ∈ Fin → X ∈ UFL
7 1 6 sylbi ⊢ X ∈ Fin → X ∈ UFL