Metamath Proof Explorer


Theorem isfin32i

Description: One half of isfin3-2 . (Contributed by Mario Carneiro, 3-Jun-2015)

Ref Expression
Assertion isfin32i ⊢ A ∈ FinIII → ¬ ω ≼ * A

Proof

Step Hyp Ref Expression
1 isfin3 ⊢ A ∈ FinIII ↔ 𝒫 A ∈ FinIV
2 isfin4-2 ⊢ 𝒫 A ∈ FinIV → 𝒫 A ∈ FinIV ↔ ¬ ω ≼ 𝒫 A
3 2 ibi ⊢ 𝒫 A ∈ FinIV → ¬ ω ≼ 𝒫 A
4 relwdom ⊢ Rel ⁡ ≼ *
5 4 brrelex1i ⊢ ω ≼ * A → ω ∈ V
6 canth2g ⊢ ω ∈ V → ω ≺ 𝒫 ω
7 sdomdom ⊢ ω ≺ 𝒫 ω → ω ≼ 𝒫 ω
8 5 6 7 3syl ⊢ ω ≼ * A → ω ≼ 𝒫 ω
9 wdompwdom ⊢ ω ≼ * A → 𝒫 ω ≼ 𝒫 A
10 domtr ⊢ ω ≼ 𝒫 ω ∧ 𝒫 ω ≼ 𝒫 A → ω ≼ 𝒫 A
11 8 9 10 syl2anc ⊢ ω ≼ * A → ω ≼ 𝒫 A
12 3 11 nsyl ⊢ 𝒫 A ∈ FinIV → ¬ ω ≼ * A
13 1 12 sylbi ⊢ A ∈ FinIII → ¬ ω ≼ * A