Metamath Proof Explorer

Theorem oi0

Description: Definition of the ordinal isomorphism when its arguments are not meaningful. (Contributed by Mario Carneiro, 25-Jun-2015)

Ref Expression
Hypothesis oicl.1 ⊢ F = OrdIso R A
Assertion oi0 ⊢ ¬ R We A ∧ R Se A → F = ∅

Proof

Step Hyp Ref Expression
1 oicl.1 ⊢ F = OrdIso R A
2 df-oi ⊢ OrdIso R A = if R We A ∧ R Se A recs ⁡ h ∈ V ⟼ ι v ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w | ∀ u ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w ¬ u R v ↾ x ∈ On | ∃ t ∈ A ∀ z ∈ recs ⁡ h ∈ V ⟼ ι v ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w | ∀ u ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w ¬ u R v x z R t ∅
3 1 2 eqtri ⊢ F = if R We A ∧ R Se A recs ⁡ h ∈ V ⟼ ι v ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w | ∀ u ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w ¬ u R v ↾ x ∈ On | ∃ t ∈ A ∀ z ∈ recs ⁡ h ∈ V ⟼ ι v ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w | ∀ u ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w ¬ u R v x z R t ∅
4 iffalse ⊢ ¬ R We A ∧ R Se A → if R We A ∧ R Se A recs ⁡ h ∈ V ⟼ ι v ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w | ∀ u ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w ¬ u R v ↾ x ∈ On | ∃ t ∈ A ∀ z ∈ recs ⁡ h ∈ V ⟼ ι v ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w | ∀ u ∈ w ∈ A | ∀ j ∈ ran ⁡ h j R w ¬ u R v x z R t ∅ = ∅
5 3 4 eqtrid ⊢ ¬ R We A ∧ R Se A → F = ∅