Step |
Hyp |
Ref |
Expression |
1 |
|
elisset |
⊢ ( 𝐴 ∈ 𝑉 → ∃ 𝑧 𝑧 = 𝐴 ) |
2 |
|
nfnfc1 |
⊢ Ⅎ 𝑥 Ⅎ 𝑥 𝐴 |
3 |
|
nfcvd |
⊢ ( Ⅎ 𝑥 𝐴 → Ⅎ 𝑥 𝑧 ) |
4 |
|
id |
⊢ ( Ⅎ 𝑥 𝐴 → Ⅎ 𝑥 𝐴 ) |
5 |
3 4
|
nfeqd |
⊢ ( Ⅎ 𝑥 𝐴 → Ⅎ 𝑥 𝑧 = 𝐴 ) |
6 |
|
eqeq1 |
⊢ ( 𝑧 = 𝑥 → ( 𝑧 = 𝐴 ↔ 𝑥 = 𝐴 ) ) |
7 |
6
|
a1i |
⊢ ( Ⅎ 𝑥 𝐴 → ( 𝑧 = 𝑥 → ( 𝑧 = 𝐴 ↔ 𝑥 = 𝐴 ) ) ) |
8 |
2 5 7
|
cbvexd |
⊢ ( Ⅎ 𝑥 𝐴 → ( ∃ 𝑧 𝑧 = 𝐴 ↔ ∃ 𝑥 𝑥 = 𝐴 ) ) |
9 |
1 8
|
syl5ib |
⊢ ( Ⅎ 𝑥 𝐴 → ( 𝐴 ∈ 𝑉 → ∃ 𝑥 𝑥 = 𝐴 ) ) |
10 |
9
|
ad2antrr |
⊢ ( ( ( Ⅎ 𝑥 𝐴 ∧ Ⅎ 𝑥 𝜓 ) ∧ ( ∀ 𝑥 ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) ∧ ∀ 𝑥 𝜑 ) ) → ( 𝐴 ∈ 𝑉 → ∃ 𝑥 𝑥 = 𝐴 ) ) |
11 |
10
|
3impia |
⊢ ( ( ( Ⅎ 𝑥 𝐴 ∧ Ⅎ 𝑥 𝜓 ) ∧ ( ∀ 𝑥 ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) ∧ ∀ 𝑥 𝜑 ) ∧ 𝐴 ∈ 𝑉 ) → ∃ 𝑥 𝑥 = 𝐴 ) |
12 |
|
biimp |
⊢ ( ( 𝜑 ↔ 𝜓 ) → ( 𝜑 → 𝜓 ) ) |
13 |
12
|
imim2i |
⊢ ( ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) → ( 𝑥 = 𝐴 → ( 𝜑 → 𝜓 ) ) ) |
14 |
13
|
com23 |
⊢ ( ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) → ( 𝜑 → ( 𝑥 = 𝐴 → 𝜓 ) ) ) |
15 |
14
|
imp |
⊢ ( ( ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) ∧ 𝜑 ) → ( 𝑥 = 𝐴 → 𝜓 ) ) |
16 |
15
|
alanimi |
⊢ ( ( ∀ 𝑥 ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) ∧ ∀ 𝑥 𝜑 ) → ∀ 𝑥 ( 𝑥 = 𝐴 → 𝜓 ) ) |
17 |
|
19.23t |
⊢ ( Ⅎ 𝑥 𝜓 → ( ∀ 𝑥 ( 𝑥 = 𝐴 → 𝜓 ) ↔ ( ∃ 𝑥 𝑥 = 𝐴 → 𝜓 ) ) ) |
18 |
17
|
adantl |
⊢ ( ( Ⅎ 𝑥 𝐴 ∧ Ⅎ 𝑥 𝜓 ) → ( ∀ 𝑥 ( 𝑥 = 𝐴 → 𝜓 ) ↔ ( ∃ 𝑥 𝑥 = 𝐴 → 𝜓 ) ) ) |
19 |
16 18
|
syl5ib |
⊢ ( ( Ⅎ 𝑥 𝐴 ∧ Ⅎ 𝑥 𝜓 ) → ( ( ∀ 𝑥 ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) ∧ ∀ 𝑥 𝜑 ) → ( ∃ 𝑥 𝑥 = 𝐴 → 𝜓 ) ) ) |
20 |
19
|
imp |
⊢ ( ( ( Ⅎ 𝑥 𝐴 ∧ Ⅎ 𝑥 𝜓 ) ∧ ( ∀ 𝑥 ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) ∧ ∀ 𝑥 𝜑 ) ) → ( ∃ 𝑥 𝑥 = 𝐴 → 𝜓 ) ) |
21 |
20
|
3adant3 |
⊢ ( ( ( Ⅎ 𝑥 𝐴 ∧ Ⅎ 𝑥 𝜓 ) ∧ ( ∀ 𝑥 ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) ∧ ∀ 𝑥 𝜑 ) ∧ 𝐴 ∈ 𝑉 ) → ( ∃ 𝑥 𝑥 = 𝐴 → 𝜓 ) ) |
22 |
11 21
|
mpd |
⊢ ( ( ( Ⅎ 𝑥 𝐴 ∧ Ⅎ 𝑥 𝜓 ) ∧ ( ∀ 𝑥 ( 𝑥 = 𝐴 → ( 𝜑 ↔ 𝜓 ) ) ∧ ∀ 𝑥 𝜑 ) ∧ 𝐴 ∈ 𝑉 ) → 𝜓 ) |