| Step | Hyp | Ref
 | Expression | 
| 1 |   | elnc 6126 | 
. . 3
⊢ (x ∈ Nc (A ∪ B) ↔ x
≈ (A ∪ B)) | 
| 2 |   | bren 6031 | 
. . . . 5
⊢ (x ≈ (A
∪ B) ↔ ∃r r:x–1-1-onto→(A ∪
B)) | 
| 3 |   | f1ocnv 5300 | 
. . . . . . 7
⊢ (r:x–1-1-onto→(A ∪
B) → ◡r:(A ∪
B)–1-1-onto→x) | 
| 4 |   | imaundi 5040 | 
. . . . . . . . . . 11
⊢ (◡r
“ (A ∪ B)) = ((◡r
“ A) ∪ (◡r
“ B)) | 
| 5 |   | imadmrn 5009 | 
. . . . . . . . . . . . 13
⊢ (◡r
“ dom ◡r) = ran ◡r | 
| 6 | 5 | a1i 10 | 
. . . . . . . . . . . 12
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
“ dom ◡r) = ran ◡r) | 
| 7 |   | f1odm 5291 | 
. . . . . . . . . . . . 13
⊢ (◡r:(A ∪
B)–1-1-onto→x →
dom ◡r = (A ∪
B)) | 
| 8 | 7 | imaeq2d 4943 | 
. . . . . . . . . . . 12
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
“ dom ◡r) = (◡r
“ (A ∪ B))) | 
| 9 |   | f1ofo 5294 | 
. . . . . . . . . . . . 13
⊢ (◡r:(A ∪
B)–1-1-onto→x →
◡r:(A ∪
B)–onto→x) | 
| 10 |   | forn 5273 | 
. . . . . . . . . . . . 13
⊢ (◡r:(A ∪
B)–onto→x →
ran ◡r = x) | 
| 11 | 9, 10 | syl 15 | 
. . . . . . . . . . . 12
⊢ (◡r:(A ∪
B)–1-1-onto→x →
ran ◡r = x) | 
| 12 | 6, 8, 11 | 3eqtr3d 2393 | 
. . . . . . . . . . 11
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
“ (A ∪ B)) = x) | 
| 13 | 4, 12 | syl5eqr 2399 | 
. . . . . . . . . 10
⊢ (◡r:(A ∪
B)–1-1-onto→x →
((◡r “ A)
∪ (◡r “ B)) =
x) | 
| 14 | 13 | adantl 452 | 
. . . . . . . . 9
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
((◡r “ A)
∪ (◡r “ B)) =
x) | 
| 15 |   | f1of1 5287 | 
. . . . . . . . . . . . . 14
⊢ (◡r:(A ∪
B)–1-1-onto→x →
◡r:(A ∪
B)–1-1→x) | 
| 16 |   | ssun1 3427 | 
. . . . . . . . . . . . . 14
⊢ A ⊆ (A ∪ B) | 
| 17 |   | f1ores 5301 | 
. . . . . . . . . . . . . 14
⊢ ((◡r:(A ∪
B)–1-1→x ∧ A ⊆ (A ∪
B)) → (◡r ↾ A):A–1-1-onto→(◡r
“ A)) | 
| 18 | 15, 16, 17 | sylancl 643 | 
. . . . . . . . . . . . 13
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
↾ A):A–1-1-onto→(◡r
“ A)) | 
| 19 |   | f1ocnv 5300 | 
. . . . . . . . . . . . 13
⊢ ((◡r ↾ A):A–1-1-onto→(◡r
“ A) → ◡(◡r ↾ A):(◡r
“ A)–1-1-onto→A) | 
| 20 |   | vex 2863 | 
. . . . . . . . . . . . . . . . 17
⊢ r ∈
V | 
| 21 | 20 | cnvex 5103 | 
. . . . . . . . . . . . . . . 16
⊢ ◡r ∈ V | 
| 22 |   | ncdisjun.1 | 
. . . . . . . . . . . . . . . 16
⊢ A ∈
V | 
| 23 | 21, 22 | resex 5118 | 
. . . . . . . . . . . . . . 15
⊢ (◡r ↾ A) ∈ V | 
| 24 | 23 | cnvex 5103 | 
. . . . . . . . . . . . . 14
⊢ ◡(◡r ↾ A) ∈ V | 
| 25 | 24 | f1oen 6034 | 
. . . . . . . . . . . . 13
⊢ (◡(◡r ↾ A):(◡r
“ A)–1-1-onto→A →
(◡r
“ A) ≈ A) | 
| 26 | 18, 19, 25 | 3syl 18 | 
. . . . . . . . . . . 12
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
“ A) ≈ A) | 
| 27 |   | elnc 6126 | 
. . . . . . . . . . . 12
⊢ ((◡r
“ A) ∈ Nc A ↔ (◡r
“ A) ≈ A) | 
| 28 | 26, 27 | sylibr 203 | 
. . . . . . . . . . 11
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
“ A) ∈ Nc A) | 
| 29 | 28 | adantl 452 | 
. . . . . . . . . 10
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
(◡r
“ A) ∈ Nc A) | 
| 30 |   | ssun2 3428 | 
. . . . . . . . . . . . . 14
⊢ B ⊆ (A ∪ B) | 
| 31 |   | f1ores 5301 | 
. . . . . . . . . . . . . 14
⊢ ((◡r:(A ∪
B)–1-1→x ∧ B ⊆ (A ∪
B)) → (◡r ↾ B):B–1-1-onto→(◡r
“ B)) | 
| 32 | 15, 30, 31 | sylancl 643 | 
. . . . . . . . . . . . 13
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
↾ B):B–1-1-onto→(◡r
“ B)) | 
| 33 |   | f1ocnv 5300 | 
. . . . . . . . . . . . 13
⊢ ((◡r ↾ B):B–1-1-onto→(◡r
“ B) → ◡(◡r ↾ B):(◡r
“ B)–1-1-onto→B) | 
| 34 |   | ncdisjun.2 | 
. . . . . . . . . . . . . . . 16
⊢ B ∈
V | 
| 35 | 21, 34 | resex 5118 | 
. . . . . . . . . . . . . . 15
⊢ (◡r ↾ B) ∈ V | 
| 36 | 35 | cnvex 5103 | 
. . . . . . . . . . . . . 14
⊢ ◡(◡r ↾ B) ∈ V | 
| 37 | 36 | f1oen 6034 | 
. . . . . . . . . . . . 13
⊢ (◡(◡r ↾ B):(◡r
“ B)–1-1-onto→B →
(◡r
“ B) ≈ B) | 
| 38 | 32, 33, 37 | 3syl 18 | 
. . . . . . . . . . . 12
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
“ B) ≈ B) | 
| 39 | 38 | adantl 452 | 
. . . . . . . . . . 11
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
(◡r
“ B) ≈ B) | 
| 40 |   | elnc 6126 | 
. . . . . . . . . . 11
⊢ ((◡r
“ B) ∈ Nc B ↔ (◡r
“ B) ≈ B) | 
| 41 | 39, 40 | sylibr 203 | 
. . . . . . . . . 10
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
(◡r
“ B) ∈ Nc B) | 
| 42 |   | df-f1 4793 | 
. . . . . . . . . . . . . 14
⊢ (◡r:(A ∪
B)–1-1→x ↔
(◡r:(A ∪
B)–→x ∧ Fun ◡◡r)) | 
| 43 | 42 | simprbi 450 | 
. . . . . . . . . . . . 13
⊢ (◡r:(A ∪
B)–1-1→x →
Fun ◡◡r) | 
| 44 |   | imain 5173 | 
. . . . . . . . . . . . 13
⊢ (Fun ◡◡r →
(◡r
“ (A ∩ B)) = ((◡r
“ A) ∩ (◡r
“ B))) | 
| 45 | 15, 43, 44 | 3syl 18 | 
. . . . . . . . . . . 12
⊢ (◡r:(A ∪
B)–1-1-onto→x →
(◡r
“ (A ∩ B)) = ((◡r
“ A) ∩ (◡r
“ B))) | 
| 46 | 45 | adantl 452 | 
. . . . . . . . . . 11
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
(◡r
“ (A ∩ B)) = ((◡r
“ A) ∩ (◡r
“ B))) | 
| 47 |   | imaeq2 4939 | 
. . . . . . . . . . . . 13
⊢ ((A ∩ B) =
∅ → (◡r
“ (A ∩ B)) = (◡r
“ ∅)) | 
| 48 |   | ima0 5014 | 
. . . . . . . . . . . . 13
⊢ (◡r
“ ∅) = ∅ | 
| 49 | 47, 48 | syl6eq 2401 | 
. . . . . . . . . . . 12
⊢ ((A ∩ B) =
∅ → (◡r
“ (A ∩ B)) = ∅) | 
| 50 | 49 | adantr 451 | 
. . . . . . . . . . 11
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
(◡r
“ (A ∩ B)) = ∅) | 
| 51 | 46, 50 | eqtr3d 2387 | 
. . . . . . . . . 10
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
((◡r “ A)
∩ (◡r “ B)) =
∅) | 
| 52 |   | eladdci 4400 | 
. . . . . . . . . 10
⊢ (((◡r
“ A) ∈ Nc A ∧ (◡r
“ B) ∈ Nc B ∧ ((◡r
“ A) ∩ (◡r
“ B)) = ∅) → ((◡r
“ A) ∪ (◡r
“ B)) ∈ ( Nc A +c Nc B)) | 
| 53 | 29, 41, 51, 52 | syl3anc 1182 | 
. . . . . . . . 9
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
((◡r “ A)
∪ (◡r “ B))
∈ ( Nc A +c Nc B)) | 
| 54 | 14, 53 | eqeltrrd 2428 | 
. . . . . . . 8
⊢ (((A ∩ B) =
∅ ∧ ◡r:(A ∪
B)–1-1-onto→x) →
x ∈ (
Nc A
+c Nc B)) | 
| 55 | 54 | ex 423 | 
. . . . . . 7
⊢ ((A ∩ B) =
∅ → (◡r:(A ∪
B)–1-1-onto→x →
x ∈ (
Nc A
+c Nc B))) | 
| 56 | 3, 55 | syl5 28 | 
. . . . . 6
⊢ ((A ∩ B) =
∅ → (r:x–1-1-onto→(A ∪
B) → x ∈ ( Nc A
+c Nc B))) | 
| 57 | 56 | exlimdv 1636 | 
. . . . 5
⊢ ((A ∩ B) =
∅ → (∃r r:x–1-1-onto→(A ∪
B) → x ∈ ( Nc A
+c Nc B))) | 
| 58 | 2, 57 | syl5bi 208 | 
. . . 4
⊢ ((A ∩ B) =
∅ → (x ≈ (A
∪ B) → x ∈ ( Nc A
+c Nc B))) | 
| 59 |   | eladdc 4399 | 
. . . . 5
⊢ (x ∈ ( Nc A
+c Nc B) ↔ ∃p ∈ Nc A∃q ∈ Nc B((p ∩ q) =
∅ ∧
x = (p
∪ q))) | 
| 60 |   | simplrl 736 | 
. . . . . . . . . 10
⊢ ((((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) ∧ (p ∩ q) =
∅) → p ∈ Nc A) | 
| 61 |   | elnc 6126 | 
. . . . . . . . . 10
⊢ (p ∈ Nc A ↔ p ≈ A) | 
| 62 | 60, 61 | sylib 188 | 
. . . . . . . . 9
⊢ ((((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) ∧ (p ∩ q) =
∅) → p ≈ A) | 
| 63 |   | simplrr 737 | 
. . . . . . . . . 10
⊢ ((((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) ∧ (p ∩ q) =
∅) → q ∈ Nc B) | 
| 64 |   | elnc 6126 | 
. . . . . . . . . 10
⊢ (q ∈ Nc B ↔ q ≈ B) | 
| 65 | 63, 64 | sylib 188 | 
. . . . . . . . 9
⊢ ((((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) ∧ (p ∩ q) =
∅) → q ≈ B) | 
| 66 |   | simpr 447 | 
. . . . . . . . 9
⊢ ((((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) ∧ (p ∩ q) =
∅) → (p ∩ q) =
∅) | 
| 67 |   | simpll 730 | 
. . . . . . . . 9
⊢ ((((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) ∧ (p ∩ q) =
∅) → (A ∩ B) =
∅) | 
| 68 |   | unen 6049 | 
. . . . . . . . 9
⊢ (((p ≈ A
∧ q
≈ B) ∧ ((p ∩
q) = ∅
∧ (A ∩
B) = ∅))
→ (p ∪ q) ≈ (A
∪ B)) | 
| 69 | 62, 65, 66, 67, 68 | syl22anc 1183 | 
. . . . . . . 8
⊢ ((((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) ∧ (p ∩ q) =
∅) → (p ∪ q)
≈ (A ∪ B)) | 
| 70 |   | breq1 4643 | 
. . . . . . . 8
⊢ (x = (p ∪
q) → (x ≈ (A
∪ B) ↔ (p ∪ q)
≈ (A ∪ B))) | 
| 71 | 69, 70 | syl5ibrcom 213 | 
. . . . . . 7
⊢ ((((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) ∧ (p ∩ q) =
∅) → (x = (p ∪
q) → x ≈ (A
∪ B))) | 
| 72 | 71 | expimpd 586 | 
. . . . . 6
⊢ (((A ∩ B) =
∅ ∧
(p ∈
Nc A ∧ q ∈ Nc B)) → (((p
∩ q) = ∅ ∧ x = (p ∪
q)) → x ≈ (A
∪ B))) | 
| 73 | 72 | rexlimdvva 2746 | 
. . . . 5
⊢ ((A ∩ B) =
∅ → (∃p ∈ Nc A∃q ∈ Nc B((p ∩ q) =
∅ ∧
x = (p
∪ q)) → x ≈ (A
∪ B))) | 
| 74 | 59, 73 | syl5bi 208 | 
. . . 4
⊢ ((A ∩ B) =
∅ → (x ∈ ( Nc A
+c Nc B) → x
≈ (A ∪ B))) | 
| 75 | 58, 74 | impbid 183 | 
. . 3
⊢ ((A ∩ B) =
∅ → (x ≈ (A
∪ B) ↔ x ∈ ( Nc A
+c Nc B))) | 
| 76 | 1, 75 | syl5bb 248 | 
. 2
⊢ ((A ∩ B) =
∅ → (x ∈ Nc (A ∪ B) ↔ x
∈ ( Nc A +c Nc B))) | 
| 77 | 76 | eqrdv 2351 | 
1
⊢ ((A ∩ B) =
∅ → Nc
(A ∪ B) = ( Nc A +c Nc B)) |