Step |
Hyp |
Ref |
Expression |
1 |
|
rexnal |
⊢ ( ∃ 𝑥 ∈ 𝐴 ¬ 𝜑 ↔ ¬ ∀ 𝑥 ∈ 𝐴 𝜑 ) |
2 |
|
rexnal |
⊢ ( ∃ 𝑦 ∈ 𝐵 ¬ 𝜓 ↔ ¬ ∀ 𝑦 ∈ 𝐵 𝜓 ) |
3 |
1 2
|
anbi12i |
⊢ ( ( ∃ 𝑥 ∈ 𝐴 ¬ 𝜑 ∧ ∃ 𝑦 ∈ 𝐵 ¬ 𝜓 ) ↔ ( ¬ ∀ 𝑥 ∈ 𝐴 𝜑 ∧ ¬ ∀ 𝑦 ∈ 𝐵 𝜓 ) ) |
4 |
|
ioran |
⊢ ( ¬ ( 𝜑 ∨ 𝜓 ) ↔ ( ¬ 𝜑 ∧ ¬ 𝜓 ) ) |
5 |
4
|
rexbii |
⊢ ( ∃ 𝑦 ∈ 𝐵 ¬ ( 𝜑 ∨ 𝜓 ) ↔ ∃ 𝑦 ∈ 𝐵 ( ¬ 𝜑 ∧ ¬ 𝜓 ) ) |
6 |
|
rexnal |
⊢ ( ∃ 𝑦 ∈ 𝐵 ¬ ( 𝜑 ∨ 𝜓 ) ↔ ¬ ∀ 𝑦 ∈ 𝐵 ( 𝜑 ∨ 𝜓 ) ) |
7 |
5 6
|
bitr3i |
⊢ ( ∃ 𝑦 ∈ 𝐵 ( ¬ 𝜑 ∧ ¬ 𝜓 ) ↔ ¬ ∀ 𝑦 ∈ 𝐵 ( 𝜑 ∨ 𝜓 ) ) |
8 |
7
|
rexbii |
⊢ ( ∃ 𝑥 ∈ 𝐴 ∃ 𝑦 ∈ 𝐵 ( ¬ 𝜑 ∧ ¬ 𝜓 ) ↔ ∃ 𝑥 ∈ 𝐴 ¬ ∀ 𝑦 ∈ 𝐵 ( 𝜑 ∨ 𝜓 ) ) |
9 |
|
reeanv |
⊢ ( ∃ 𝑥 ∈ 𝐴 ∃ 𝑦 ∈ 𝐵 ( ¬ 𝜑 ∧ ¬ 𝜓 ) ↔ ( ∃ 𝑥 ∈ 𝐴 ¬ 𝜑 ∧ ∃ 𝑦 ∈ 𝐵 ¬ 𝜓 ) ) |
10 |
|
rexnal |
⊢ ( ∃ 𝑥 ∈ 𝐴 ¬ ∀ 𝑦 ∈ 𝐵 ( 𝜑 ∨ 𝜓 ) ↔ ¬ ∀ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐵 ( 𝜑 ∨ 𝜓 ) ) |
11 |
8 9 10
|
3bitr3ri |
⊢ ( ¬ ∀ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐵 ( 𝜑 ∨ 𝜓 ) ↔ ( ∃ 𝑥 ∈ 𝐴 ¬ 𝜑 ∧ ∃ 𝑦 ∈ 𝐵 ¬ 𝜓 ) ) |
12 |
|
ioran |
⊢ ( ¬ ( ∀ 𝑥 ∈ 𝐴 𝜑 ∨ ∀ 𝑦 ∈ 𝐵 𝜓 ) ↔ ( ¬ ∀ 𝑥 ∈ 𝐴 𝜑 ∧ ¬ ∀ 𝑦 ∈ 𝐵 𝜓 ) ) |
13 |
3 11 12
|
3bitr4i |
⊢ ( ¬ ∀ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐵 ( 𝜑 ∨ 𝜓 ) ↔ ¬ ( ∀ 𝑥 ∈ 𝐴 𝜑 ∨ ∀ 𝑦 ∈ 𝐵 𝜓 ) ) |
14 |
13
|
con4bii |
⊢ ( ∀ 𝑥 ∈ 𝐴 ∀ 𝑦 ∈ 𝐵 ( 𝜑 ∨ 𝜓 ) ↔ ( ∀ 𝑥 ∈ 𝐴 𝜑 ∨ ∀ 𝑦 ∈ 𝐵 𝜓 ) ) |