Proof of Theorem cla43egv
| Step | Hyp | Ref
| Expression |
| 1 | | cla43egv.1 |
. . . . 5
⊢ ((x = A ⋀ y = B ⋀ z = C) →
(φ ↔ ψ)) |
| 2 | 1 | biimprcd 156 |
. . . 4
⊢ (ψ → ((x = A ⋀ y = B ⋀ z = C) →
φ)) |
| 3 | 2 | 19.22dv 1292 |
. . 3
⊢ (ψ → (∃z(x = A ⋀ y = B ⋀ z = C) →
∃zφ)) |
| 4 | 3 | 19.22dvv 1294 |
. 2
⊢ (ψ → (∃x∃y∃z(x = A ⋀ y = B ⋀ z = C) →
∃x∃y∃zφ)) |
| 5 | | elex 1822 |
. . . 4
⊢ (A ∈ R → ∃x x = A) |
| 6 | | elex 1822 |
. . . 4
⊢ (B ∈ S → ∃y y = B) |
| 7 | | elex 1822 |
. . . 4
⊢ (C ∈ T → ∃z z = C) |
| 8 | 5, 6, 7 | 3anim123i 823 |
. . 3
⊢ ((A ∈ R ⋀ B ∈ S ⋀ C ∈ T) → (∃x x = A ⋀ ∃y y = B ⋀ ∃z z = C)) |
| 9 | | eeeanv 1326 |
. . 3
⊢ (∃x∃y∃z(x = A ⋀ y = B ⋀ z = C) ↔
(∃x
x = A
⋀ ∃y y = B ⋀ ∃z z = C)) |
| 10 | 8, 9 | sylibr 200 |
. 2
⊢ ((A ∈ R ⋀ B ∈ S ⋀ C ∈ T) → ∃x∃y∃z(x = A ⋀ y = B ⋀ z = C)) |
| 11 | 4, 10 | syl5com 52 |
1
⊢ ((A ∈ R ⋀ B ∈ S ⋀ C ∈ T) → (ψ
→ ∃x∃y∃zφ)) |