Proof of Theorem fun11
| Step | Hyp | Ref
 | Expression | 
| 1 |   | dfbi2 609 | 
. . . . . . . 8
⊢ ((x = z ↔
y = w)
↔ ((x = z → y =
w) ∧
(y = w
→ x = z))) | 
| 2 | 1 | imbi2i 303 | 
. . . . . . 7
⊢ (((xAy ∧ zAw) → (x =
z ↔ y = w)) ↔
((xAy ∧ zAw) →
((x = z
→ y = w) ∧ (y = w →
x = z)))) | 
| 3 |   | pm4.76 836 | 
. . . . . . 7
⊢ ((((xAy ∧ zAw) → (x =
z → y = w)) ∧ ((xAy ∧ zAw) →
(y = w
→ x = z))) ↔ ((xAy ∧ zAw) → ((x =
z → y = w) ∧ (y = w → x =
z)))) | 
| 4 |   | bi2.04 350 | 
. . . . . . . 8
⊢ (((xAy ∧ zAw) → (x =
z → y = w)) ↔
(x = z
→ ((xAy ∧ zAw) →
y = w))) | 
| 5 |   | bi2.04 350 | 
. . . . . . . 8
⊢ (((xAy ∧ zAw) → (y =
w → x = z)) ↔
(y = w
→ ((xAy ∧ zAw) →
x = z))) | 
| 6 | 4, 5 | anbi12i 678 | 
. . . . . . 7
⊢ ((((xAy ∧ zAw) → (x =
z → y = w)) ∧ ((xAy ∧ zAw) →
(y = w
→ x = z))) ↔ ((x
= z → ((xAy ∧ zAw) → y =
w)) ∧
(y = w
→ ((xAy ∧ zAw) →
x = z)))) | 
| 7 | 2, 3, 6 | 3bitr2i 264 | 
. . . . . 6
⊢ (((xAy ∧ zAw) → (x =
z ↔ y = w)) ↔
((x = z
→ ((xAy ∧ zAw) →
y = w))
∧ (y =
w → ((xAy ∧ zAw) → x =
z)))) | 
| 8 | 7 | 2albii 1567 | 
. . . . 5
⊢ (∀x∀y((xAy ∧ zAw) → (x =
z ↔ y = w)) ↔
∀x∀y((x = z →
((xAy ∧ zAw) →
y = w))
∧ (y =
w → ((xAy ∧ zAw) → x =
z)))) | 
| 9 |   | 19.26-2 1594 | 
. . . . 5
⊢ (∀x∀y((x = z →
((xAy ∧ zAw) →
y = w))
∧ (y =
w → ((xAy ∧ zAw) → x =
z))) ↔ (∀x∀y(x = z →
((xAy ∧ zAw) →
y = w))
∧ ∀x∀y(y = w →
((xAy ∧ zAw) →
x = z)))) | 
| 10 |   | alcom 1737 | 
. . . . . . 7
⊢ (∀x∀y(x = z →
((xAy ∧ zAw) →
y = w))
↔ ∀y∀x(x = z → ((xAy ∧ zAw) → y =
w))) | 
| 11 |   | nfv 1619 | 
. . . . . . . . 9
⊢ Ⅎx((zAy ∧ zAw) →
y = w) | 
| 12 |   | breq1 4643 | 
. . . . . . . . . . 11
⊢ (x = z →
(xAy ↔
zAy)) | 
| 13 | 12 | anbi1d 685 | 
. . . . . . . . . 10
⊢ (x = z →
((xAy ∧ zAw) ↔
(zAy ∧ zAw))) | 
| 14 | 13 | imbi1d 308 | 
. . . . . . . . 9
⊢ (x = z →
(((xAy ∧ zAw) →
y = w)
↔ ((zAy ∧ zAw) →
y = w))) | 
| 15 | 11, 14 | equsal 1960 | 
. . . . . . . 8
⊢ (∀x(x = z →
((xAy ∧ zAw) →
y = w))
↔ ((zAy ∧ zAw) →
y = w)) | 
| 16 | 15 | albii 1566 | 
. . . . . . 7
⊢ (∀y∀x(x = z →
((xAy ∧ zAw) →
y = w))
↔ ∀y((zAy ∧ zAw) →
y = w)) | 
| 17 | 10, 16 | bitri 240 | 
. . . . . 6
⊢ (∀x∀y(x = z →
((xAy ∧ zAw) →
y = w))
↔ ∀y((zAy ∧ zAw) →
y = w)) | 
| 18 |   | nfv 1619 | 
. . . . . . . 8
⊢ Ⅎy((xAw ∧ zAw) →
x = z) | 
| 19 |   | breq2 4644 | 
. . . . . . . . . 10
⊢ (y = w →
(xAy ↔
xAw)) | 
| 20 | 19 | anbi1d 685 | 
. . . . . . . . 9
⊢ (y = w →
((xAy ∧ zAw) ↔
(xAw ∧ zAw))) | 
| 21 | 20 | imbi1d 308 | 
. . . . . . . 8
⊢ (y = w →
(((xAy ∧ zAw) →
x = z)
↔ ((xAw ∧ zAw) →
x = z))) | 
| 22 | 18, 21 | equsal 1960 | 
. . . . . . 7
⊢ (∀y(y = w →
((xAy ∧ zAw) →
x = z))
↔ ((xAw ∧ zAw) →
x = z)) | 
| 23 | 22 | albii 1566 | 
. . . . . 6
⊢ (∀x∀y(y = w →
((xAy ∧ zAw) →
x = z))
↔ ∀x((xAw ∧ zAw) →
x = z)) | 
| 24 | 17, 23 | anbi12i 678 | 
. . . . 5
⊢ ((∀x∀y(x = z →
((xAy ∧ zAw) →
y = w))
∧ ∀x∀y(y = w →
((xAy ∧ zAw) →
x = z))) ↔ (∀y((zAy ∧ zAw) → y =
w) ∧ ∀x((xAw ∧ zAw) → x =
z))) | 
| 25 | 8, 9, 24 | 3bitri 262 | 
. . . 4
⊢ (∀x∀y((xAy ∧ zAw) → (x =
z ↔ y = w)) ↔
(∀y((zAy ∧ zAw) →
y = w)
∧ ∀x((xAw ∧ zAw) → x =
z))) | 
| 26 | 25 | 2albii 1567 | 
. . 3
⊢ (∀z∀w∀x∀y((xAy ∧ zAw) → (x =
z ↔ y = w)) ↔
∀z∀w(∀y((zAy ∧ zAw) → y =
w) ∧ ∀x((xAw ∧ zAw) → x =
z))) | 
| 27 |   | 19.26-2 1594 | 
. . 3
⊢ (∀z∀w(∀y((zAy ∧ zAw) → y =
w) ∧ ∀x((xAw ∧ zAw) → x =
z)) ↔ (∀z∀w∀y((zAy ∧ zAw) → y =
w) ∧ ∀z∀w∀x((xAw ∧ zAw) → x =
z))) | 
| 28 | 26, 27 | bitr2i 241 | 
. 2
⊢ ((∀z∀w∀y((zAy ∧ zAw) → y =
w) ∧ ∀z∀w∀x((xAw ∧ zAw) → x =
z)) ↔ ∀z∀w∀x∀y((xAy ∧ zAw) → (x =
z ↔ y = w))) | 
| 29 |   | dffun2 5120 | 
. . . 4
⊢ (Fun A ↔ ∀z∀y∀w((zAy ∧ zAw) → y =
w)) | 
| 30 |   | alcom 1737 | 
. . . . 5
⊢ (∀y∀w((zAy ∧ zAw) → y =
w) ↔ ∀w∀y((zAy ∧ zAw) → y =
w)) | 
| 31 | 30 | albii 1566 | 
. . . 4
⊢ (∀z∀y∀w((zAy ∧ zAw) → y =
w) ↔ ∀z∀w∀y((zAy ∧ zAw) → y =
w)) | 
| 32 | 29, 31 | bitri 240 | 
. . 3
⊢ (Fun A ↔ ∀z∀w∀y((zAy ∧ zAw) → y =
w)) | 
| 33 |   | brcnv 4893 | 
. . . . . . . 8
⊢ (w◡Ax ↔
xAw) | 
| 34 |   | brcnv 4893 | 
. . . . . . . 8
⊢ (w◡Az ↔
zAw) | 
| 35 | 33, 34 | anbi12i 678 | 
. . . . . . 7
⊢ ((w◡Ax ∧ w◡Az) ↔
(xAw ∧ zAw)) | 
| 36 | 35 | imbi1i 315 | 
. . . . . 6
⊢ (((w◡Ax ∧ w◡Az) →
x = z)
↔ ((xAw ∧ zAw) →
x = z)) | 
| 37 | 36 | albii 1566 | 
. . . . 5
⊢ (∀z((w◡Ax ∧ w◡Az) →
x = z)
↔ ∀z((xAw ∧ zAw) →
x = z)) | 
| 38 | 37 | 2albii 1567 | 
. . . 4
⊢ (∀w∀x∀z((w◡Ax ∧ w◡Az) →
x = z)
↔ ∀w∀x∀z((xAw ∧ zAw) →
x = z)) | 
| 39 |   | dffun2 5120 | 
. . . 4
⊢ (Fun ◡A ↔
∀w∀x∀z((w◡Ax ∧ w◡Az) →
x = z)) | 
| 40 |   | alrot3 1738 | 
. . . 4
⊢ (∀z∀w∀x((xAw ∧ zAw) → x =
z) ↔ ∀w∀x∀z((xAw ∧ zAw) → x =
z)) | 
| 41 | 38, 39, 40 | 3bitr4i 268 | 
. . 3
⊢ (Fun ◡A ↔
∀z∀w∀x((xAw ∧ zAw) → x =
z)) | 
| 42 | 32, 41 | anbi12i 678 | 
. 2
⊢ ((Fun A ∧ Fun ◡A)
↔ (∀z∀w∀y((zAy ∧ zAw) →
y = w)
∧ ∀z∀w∀x((xAw ∧ zAw) → x =
z))) | 
| 43 |   | alrot4 1739 | 
. 2
⊢ (∀x∀y∀z∀w((xAy ∧ zAw) → (x =
z ↔ y = w)) ↔
∀z∀w∀x∀y((xAy ∧ zAw) → (x =
z ↔ y = w))) | 
| 44 | 28, 42, 43 | 3bitr4i 268 | 
1
⊢ ((Fun A ∧ Fun ◡A)
↔ ∀x∀y∀z∀w((xAy ∧ zAw) →
(x = z
↔ y = w))) |