Step |
Hyp |
Ref |
Expression |
1 |
|
simpl |
⊢ ( ( ∀ 𝑥 Ⅎ' 𝑦 𝜑 ∧ Ⅎ' 𝑥 ∀ 𝑦 𝜓 ) → ∀ 𝑥 Ⅎ' 𝑦 𝜑 ) |
2 |
|
bj-19.21t |
⊢ ( Ⅎ' 𝑦 𝜑 → ( ∀ 𝑦 ( 𝜑 → 𝜓 ) ↔ ( 𝜑 → ∀ 𝑦 𝜓 ) ) ) |
3 |
1 2
|
sylg |
⊢ ( ( ∀ 𝑥 Ⅎ' 𝑦 𝜑 ∧ Ⅎ' 𝑥 ∀ 𝑦 𝜓 ) → ∀ 𝑥 ( ∀ 𝑦 ( 𝜑 → 𝜓 ) ↔ ( 𝜑 → ∀ 𝑦 𝜓 ) ) ) |
4 |
|
albi |
⊢ ( ∀ 𝑥 ( ∀ 𝑦 ( 𝜑 → 𝜓 ) ↔ ( 𝜑 → ∀ 𝑦 𝜓 ) ) → ( ∀ 𝑥 ∀ 𝑦 ( 𝜑 → 𝜓 ) ↔ ∀ 𝑥 ( 𝜑 → ∀ 𝑦 𝜓 ) ) ) |
5 |
3 4
|
syl |
⊢ ( ( ∀ 𝑥 Ⅎ' 𝑦 𝜑 ∧ Ⅎ' 𝑥 ∀ 𝑦 𝜓 ) → ( ∀ 𝑥 ∀ 𝑦 ( 𝜑 → 𝜓 ) ↔ ∀ 𝑥 ( 𝜑 → ∀ 𝑦 𝜓 ) ) ) |
6 |
|
bj-19.23t |
⊢ ( Ⅎ' 𝑥 ∀ 𝑦 𝜓 → ( ∀ 𝑥 ( 𝜑 → ∀ 𝑦 𝜓 ) ↔ ( ∃ 𝑥 𝜑 → ∀ 𝑦 𝜓 ) ) ) |
7 |
6
|
adantl |
⊢ ( ( ∀ 𝑥 Ⅎ' 𝑦 𝜑 ∧ Ⅎ' 𝑥 ∀ 𝑦 𝜓 ) → ( ∀ 𝑥 ( 𝜑 → ∀ 𝑦 𝜓 ) ↔ ( ∃ 𝑥 𝜑 → ∀ 𝑦 𝜓 ) ) ) |
8 |
5 7
|
bitrd |
⊢ ( ( ∀ 𝑥 Ⅎ' 𝑦 𝜑 ∧ Ⅎ' 𝑥 ∀ 𝑦 𝜓 ) → ( ∀ 𝑥 ∀ 𝑦 ( 𝜑 → 𝜓 ) ↔ ( ∃ 𝑥 𝜑 → ∀ 𝑦 𝜓 ) ) ) |