Proof of Theorem rspct
| Step | Hyp | Ref
| Expression |
| 1 | | df-ral 2620 |
. . . 4
⊢ (∀x ∈ B φ ↔ ∀x(x ∈ B → φ)) |
| 2 | | eleq1 2413 |
. . . . . . . . . 10
⊢ (x = A →
(x ∈
B ↔ A ∈ B)) |
| 3 | 2 | adantr 451 |
. . . . . . . . 9
⊢ ((x = A ∧ (φ ↔
ψ)) → (x ∈ B ↔ A ∈ B)) |
| 4 | | simpr 447 |
. . . . . . . . 9
⊢ ((x = A ∧ (φ ↔
ψ)) → (φ ↔ ψ)) |
| 5 | 3, 4 | imbi12d 311 |
. . . . . . . 8
⊢ ((x = A ∧ (φ ↔
ψ)) → ((x ∈ B → φ)
↔ (A ∈ B →
ψ))) |
| 6 | 5 | ex 423 |
. . . . . . 7
⊢ (x = A →
((φ ↔ ψ) → ((x ∈ B → φ)
↔ (A ∈ B →
ψ)))) |
| 7 | 6 | a2i 12 |
. . . . . 6
⊢ ((x = A →
(φ ↔ ψ)) → (x = A →
((x ∈
B → φ) ↔ (A ∈ B → ψ)))) |
| 8 | 7 | alimi 1559 |
. . . . 5
⊢ (∀x(x = A →
(φ ↔ ψ)) → ∀x(x = A →
((x ∈
B → φ) ↔ (A ∈ B → ψ)))) |
| 9 | | nfv 1619 |
. . . . . . 7
⊢ Ⅎx A ∈ B |
| 10 | | rspct.1 |
. . . . . . 7
⊢ Ⅎxψ |
| 11 | 9, 10 | nfim 1813 |
. . . . . 6
⊢ Ⅎx(A ∈ B →
ψ) |
| 12 | | nfcv 2490 |
. . . . . 6
⊢
ℲxA |
| 13 | 11, 12 | spcgft 2932 |
. . . . 5
⊢ (∀x(x = A →
((x ∈
B → φ) ↔ (A ∈ B → ψ))) → (A ∈ B → (∀x(x ∈ B → φ)
→ (A ∈ B →
ψ)))) |
| 14 | 8, 13 | syl 15 |
. . . 4
⊢ (∀x(x = A →
(φ ↔ ψ)) → (A ∈ B → (∀x(x ∈ B → φ)
→ (A ∈ B →
ψ)))) |
| 15 | 1, 14 | syl7bi 221 |
. . 3
⊢ (∀x(x = A →
(φ ↔ ψ)) → (A ∈ B → (∀x ∈ B φ → (A ∈ B → ψ)))) |
| 16 | 15 | com34 77 |
. 2
⊢ (∀x(x = A →
(φ ↔ ψ)) → (A ∈ B → (A
∈ B
→ (∀x ∈ B φ →
ψ)))) |
| 17 | 16 | pm2.43d 44 |
1
⊢ (∀x(x = A →
(φ ↔ ψ)) → (A ∈ B → (∀x ∈ B φ → ψ))) |