| Step | Hyp | Ref
 | Expression | 
| 1 |   | brex 4690 | 
. 2
⊢ (A ≈ B
→ (A ∈ V ∧ B ∈
V)) | 
| 2 |   | brex 4690 | 
. . 3
⊢ (℘1A ≈ ℘1B → (℘1A ∈ V ∧ ℘1B ∈
V)) | 
| 3 |   | pw1exb 4327 | 
. . . 4
⊢ (℘1A ∈ V ↔
A ∈
V) | 
| 4 |   | pw1exb 4327 | 
. . . 4
⊢ (℘1B ∈ V ↔
B ∈
V) | 
| 5 | 3, 4 | anbi12i 678 | 
. . 3
⊢ ((℘1A ∈ V ∧ ℘1B ∈ V) ↔
(A ∈ V
∧ B ∈ V)) | 
| 6 | 2, 5 | sylib 188 | 
. 2
⊢ (℘1A ≈ ℘1B → (A
∈ V ∧
B ∈
V)) | 
| 7 |   | breq1 4643 | 
. . . 4
⊢ (a = A →
(a ≈ b ↔ A
≈ b)) | 
| 8 |   | pw1eq 4144 | 
. . . . 5
⊢ (a = A →
℘1a = ℘1A) | 
| 9 | 8 | breq1d 4650 | 
. . . 4
⊢ (a = A →
(℘1a ≈ ℘1b ↔ ℘1A ≈ ℘1b)) | 
| 10 | 7, 9 | bibi12d 312 | 
. . 3
⊢ (a = A →
((a ≈ b ↔ ℘1a ≈ ℘1b) ↔ (A
≈ b ↔ ℘1A ≈ ℘1b))) | 
| 11 |   | breq2 4644 | 
. . . 4
⊢ (b = B →
(A ≈ b ↔ A
≈ B)) | 
| 12 |   | pw1eq 4144 | 
. . . . 5
⊢ (b = B →
℘1b = ℘1B) | 
| 13 | 12 | breq2d 4652 | 
. . . 4
⊢ (b = B →
(℘1A ≈ ℘1b ↔ ℘1A ≈ ℘1B)) | 
| 14 | 11, 13 | bibi12d 312 | 
. . 3
⊢ (b = B →
((A ≈ b ↔ ℘1A ≈ ℘1b) ↔ (A
≈ B ↔ ℘1A ≈ ℘1B))) | 
| 15 |   | bren 6031 | 
. . . . 5
⊢ (a ≈ b
↔ ∃f f:a–1-1-onto→b) | 
| 16 |   | f1ofun 5290 | 
. . . . . . . . . 10
⊢ (f:a–1-1-onto→b →
Fun f) | 
| 17 |   | funsi 5521 | 
. . . . . . . . . 10
⊢ (Fun f → Fun  SI
f) | 
| 18 | 16, 17 | syl 15 | 
. . . . . . . . 9
⊢ (f:a–1-1-onto→b →
Fun  SI f) | 
| 19 |   | f1odm 5291 | 
. . . . . . . . . 10
⊢ (f:a–1-1-onto→b →
dom f = a) | 
| 20 |   | dmsi 5520 | 
. . . . . . . . . . 11
⊢ dom  SI f = ℘1dom f | 
| 21 |   | pw1eq 4144 | 
. . . . . . . . . . 11
⊢ (dom f = a →
℘1dom f = ℘1a) | 
| 22 | 20, 21 | syl5eq 2397 | 
. . . . . . . . . 10
⊢ (dom f = a → dom
 SI f = ℘1a) | 
| 23 | 19, 22 | syl 15 | 
. . . . . . . . 9
⊢ (f:a–1-1-onto→b →
dom  SI f =
℘1a) | 
| 24 |   | df-fn 4791 | 
. . . . . . . . 9
⊢ ( SI f Fn ℘1a ↔ (Fun  SI
f ∧
dom  SI f =
℘1a)) | 
| 25 | 18, 23, 24 | sylanbrc 645 | 
. . . . . . . 8
⊢ (f:a–1-1-onto→b →
 SI f Fn ℘1a) | 
| 26 |   | f1of1 5287 | 
. . . . . . . . . . 11
⊢ (f:a–1-1-onto→b →
f:a–1-1→b) | 
| 27 |   | df-f1 4793 | 
. . . . . . . . . . . 12
⊢ (f:a–1-1→b
↔ (f:a–→b
∧ Fun ◡f)) | 
| 28 | 27 | simprbi 450 | 
. . . . . . . . . . 11
⊢ (f:a–1-1→b
→ Fun ◡f) | 
| 29 |   | funsi 5521 | 
. . . . . . . . . . 11
⊢ (Fun ◡f →
Fun  SI ◡f) | 
| 30 | 26, 28, 29 | 3syl 18 | 
. . . . . . . . . 10
⊢ (f:a–1-1-onto→b →
Fun  SI ◡f) | 
| 31 |   | cnvsi 5519 | 
. . . . . . . . . . 11
⊢ ◡ SI f =  SI ◡f | 
| 32 | 31 | funeqi 5129 | 
. . . . . . . . . 10
⊢ (Fun ◡ SI f ↔ Fun  SI ◡f) | 
| 33 | 30, 32 | sylibr 203 | 
. . . . . . . . 9
⊢ (f:a–1-1-onto→b →
Fun ◡ SI
f) | 
| 34 |   | f1ofo 5294 | 
. . . . . . . . . 10
⊢ (f:a–1-1-onto→b →
f:a–onto→b) | 
| 35 |   | forn 5273 | 
. . . . . . . . . 10
⊢ (f:a–onto→b
→ ran f = b) | 
| 36 |   | rnsi 5522 | 
. . . . . . . . . . . 12
⊢ ran  SI f = ℘1ran f | 
| 37 |   | dfrn4 4905 | 
. . . . . . . . . . . 12
⊢ ran  SI f = dom ◡ SI f | 
| 38 | 36, 37 | eqtr3i 2375 | 
. . . . . . . . . . 11
⊢ ℘1ran f = dom ◡ SI f | 
| 39 |   | pw1eq 4144 | 
. . . . . . . . . . 11
⊢ (ran f = b →
℘1ran f = ℘1b) | 
| 40 | 38, 39 | syl5eqr 2399 | 
. . . . . . . . . 10
⊢ (ran f = b → dom
◡ SI
f = ℘1b) | 
| 41 | 34, 35, 40 | 3syl 18 | 
. . . . . . . . 9
⊢ (f:a–1-1-onto→b →
dom ◡ SI
f = ℘1b) | 
| 42 |   | df-fn 4791 | 
. . . . . . . . 9
⊢ (◡ SI f Fn ℘1b ↔ (Fun ◡ SI f ∧ dom ◡ SI f = ℘1b)) | 
| 43 | 33, 41, 42 | sylanbrc 645 | 
. . . . . . . 8
⊢ (f:a–1-1-onto→b →
◡ SI
f Fn ℘1b) | 
| 44 |   | dff1o4 5295 | 
. . . . . . . 8
⊢ ( SI f:℘1a–1-1-onto→℘1b ↔ ( SI f Fn ℘1a ∧ ◡ SI f Fn ℘1b)) | 
| 45 | 25, 43, 44 | sylanbrc 645 | 
. . . . . . 7
⊢ (f:a–1-1-onto→b →
 SI f:℘1a–1-1-onto→℘1b) | 
| 46 |   | vex 2863 | 
. . . . . . . . 9
⊢ f ∈
V | 
| 47 | 46 | siex 4754 | 
. . . . . . . 8
⊢  SI f ∈ V | 
| 48 | 47 | f1oen 6034 | 
. . . . . . 7
⊢ ( SI f:℘1a–1-1-onto→℘1b → ℘1a ≈ ℘1b) | 
| 49 | 45, 48 | syl 15 | 
. . . . . 6
⊢ (f:a–1-1-onto→b →
℘1a ≈ ℘1b) | 
| 50 | 49 | exlimiv 1634 | 
. . . . 5
⊢ (∃f f:a–1-1-onto→b →
℘1a ≈ ℘1b) | 
| 51 | 15, 50 | sylbi 187 | 
. . . 4
⊢ (a ≈ b
→ ℘1a ≈ ℘1b) | 
| 52 |   | bren 6031 | 
. . . . 5
⊢ (℘1a ≈ ℘1b ↔ ∃g g:℘1a–1-1-onto→℘1b) | 
| 53 |   | f1ofun 5290 | 
. . . . . . . . . . . . . 14
⊢ (g:℘1a–1-1-onto→℘1b → Fun g) | 
| 54 |   | fununiq 5518 | 
. . . . . . . . . . . . . . . 16
⊢ ((Fun g ∧ {x}g{y} ∧ {x}g{z}) → {y} =
{z}) | 
| 55 |   | vex 2863 | 
. . . . . . . . . . . . . . . . 17
⊢ y ∈
V | 
| 56 | 55 | sneqb 3877 | 
. . . . . . . . . . . . . . . 16
⊢ ({y} = {z} ↔
y = z) | 
| 57 | 54, 56 | sylib 188 | 
. . . . . . . . . . . . . . 15
⊢ ((Fun g ∧ {x}g{y} ∧ {x}g{z}) → y =
z) | 
| 58 | 57 | 3expib 1154 | 
. . . . . . . . . . . . . 14
⊢ (Fun g → (({x}g{y} ∧ {x}g{z}) → y =
z)) | 
| 59 | 53, 58 | syl 15 | 
. . . . . . . . . . . . 13
⊢ (g:℘1a–1-1-onto→℘1b → (({x}g{y} ∧ {x}g{z}) → y =
z)) | 
| 60 | 59 | alrimivv 1632 | 
. . . . . . . . . . . 12
⊢ (g:℘1a–1-1-onto→℘1b → ∀y∀z(({x}g{y} ∧ {x}g{z}) → y =
z)) | 
| 61 |   | sneq 3745 | 
. . . . . . . . . . . . . 14
⊢ (y = z →
{y} = {z}) | 
| 62 | 61 | breq2d 4652 | 
. . . . . . . . . . . . 13
⊢ (y = z →
({x}g{y} ↔
{x}g{z})) | 
| 63 | 62 | mo4 2237 | 
. . . . . . . . . . . 12
⊢ (∃*y{x}g{y} ↔ ∀y∀z(({x}g{y} ∧ {x}g{z}) → y =
z)) | 
| 64 | 60, 63 | sylibr 203 | 
. . . . . . . . . . 11
⊢ (g:℘1a–1-1-onto→℘1b → ∃*y{x}g{y}) | 
| 65 | 64 | alrimiv 1631 | 
. . . . . . . . . 10
⊢ (g:℘1a–1-1-onto→℘1b → ∀x∃*y{x}g{y}) | 
| 66 |   | funopab 5140 | 
. . . . . . . . . 10
⊢ (Fun {〈x, y〉 ∣ {x}g{y}} ↔
∀x∃*y{x}g{y}) | 
| 67 | 65, 66 | sylibr 203 | 
. . . . . . . . 9
⊢ (g:℘1a–1-1-onto→℘1b → Fun {〈x, y〉 ∣ {x}g{y}}) | 
| 68 |   | dmopab 4916 | 
. . . . . . . . . 10
⊢ dom {〈x, y〉 ∣ {x}g{y}} =
{x ∣
∃y{x}g{y}} | 
| 69 |   | eldm 4899 | 
. . . . . . . . . . . . . . 15
⊢ ({x} ∈ dom g ↔ ∃z{x}gz) | 
| 70 |   | brelrn 4961 | 
. . . . . . . . . . . . . . . . 17
⊢ ({x}gz → z ∈ ran g) | 
| 71 |   | f1ofo 5294 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (g:℘1a–1-1-onto→℘1b → g:℘1a–onto→℘1b) | 
| 72 |   | forn 5273 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (g:℘1a–onto→℘1b → ran g =
℘1b) | 
| 73 | 71, 72 | syl 15 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (g:℘1a–1-1-onto→℘1b → ran g =
℘1b) | 
| 74 | 73 | eleq2d 2420 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (g:℘1a–1-1-onto→℘1b → (z
∈ ran g
↔ z ∈ ℘1b)) | 
| 75 |   | elpw1 4145 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (z ∈ ℘1b ↔ ∃w ∈ b z = {w}) | 
| 76 |   | breq2 4644 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ (z = {w} →
({x}gz ↔
{x}g{w})) | 
| 77 |   | vex 2863 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ w ∈
V | 
| 78 |   | sneq 3745 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (y = w →
{y} = {w}) | 
| 79 | 78 | breq2d 4652 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ (y = w →
({x}g{y} ↔
{x}g{w})) | 
| 80 | 77, 79 | spcev 2947 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ ({x}g{w} → ∃y{x}g{y}) | 
| 81 | 76, 80 | syl6bi 219 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (z = {w} →
({x}gz → ∃y{x}g{y})) | 
| 82 | 81 | rexlimivw 2735 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (∃w ∈ b z = {w} →
({x}gz → ∃y{x}g{y})) | 
| 83 | 75, 82 | sylbi 187 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (z ∈ ℘1b → ({x}gz → ∃y{x}g{y})) | 
| 84 | 74, 83 | syl6bi 219 | 
. . . . . . . . . . . . . . . . . 18
⊢ (g:℘1a–1-1-onto→℘1b → (z
∈ ran g
→ ({x}gz → ∃y{x}g{y}))) | 
| 85 | 84 | com23 72 | 
. . . . . . . . . . . . . . . . 17
⊢ (g:℘1a–1-1-onto→℘1b → ({x}gz → (z
∈ ran g
→ ∃y{x}g{y}))) | 
| 86 | 70, 85 | mpdi 38 | 
. . . . . . . . . . . . . . . 16
⊢ (g:℘1a–1-1-onto→℘1b → ({x}gz → ∃y{x}g{y})) | 
| 87 | 86 | exlimdv 1636 | 
. . . . . . . . . . . . . . 15
⊢ (g:℘1a–1-1-onto→℘1b → (∃z{x}gz → ∃y{x}g{y})) | 
| 88 | 69, 87 | syl5bi 208 | 
. . . . . . . . . . . . . 14
⊢ (g:℘1a–1-1-onto→℘1b → ({x}
∈ dom g
→ ∃y{x}g{y})) | 
| 89 |   | breldm 4912 | 
. . . . . . . . . . . . . . 15
⊢ ({x}g{y} → {x}
∈ dom g) | 
| 90 | 89 | exlimiv 1634 | 
. . . . . . . . . . . . . 14
⊢ (∃y{x}g{y} → {x}
∈ dom g) | 
| 91 | 88, 90 | impbid1 194 | 
. . . . . . . . . . . . 13
⊢ (g:℘1a–1-1-onto→℘1b → ({x}
∈ dom g
↔ ∃y{x}g{y})) | 
| 92 |   | f1odm 5291 | 
. . . . . . . . . . . . . 14
⊢ (g:℘1a–1-1-onto→℘1b → dom g =
℘1a) | 
| 93 | 92 | eleq2d 2420 | 
. . . . . . . . . . . . 13
⊢ (g:℘1a–1-1-onto→℘1b → ({x}
∈ dom g
↔ {x} ∈ ℘1a)) | 
| 94 | 91, 93 | bitr3d 246 | 
. . . . . . . . . . . 12
⊢ (g:℘1a–1-1-onto→℘1b → (∃y{x}g{y} ↔ {x}
∈ ℘1a)) | 
| 95 |   | snelpw1 4147 | 
. . . . . . . . . . . 12
⊢ ({x} ∈ ℘1a ↔ x ∈ a) | 
| 96 | 94, 95 | syl6bb 252 | 
. . . . . . . . . . 11
⊢ (g:℘1a–1-1-onto→℘1b → (∃y{x}g{y} ↔ x
∈ a)) | 
| 97 | 96 | eqabcdv 2470 | 
. . . . . . . . . 10
⊢ (g:℘1a–1-1-onto→℘1b → {x
∣ ∃y{x}g{y}} = a) | 
| 98 | 68, 97 | syl5eq 2397 | 
. . . . . . . . 9
⊢ (g:℘1a–1-1-onto→℘1b → dom {〈x, y〉 ∣ {x}g{y}} = a) | 
| 99 |   | df-fn 4791 | 
. . . . . . . . 9
⊢ ({〈x, y〉 ∣ {x}g{y}} Fn
a ↔ (Fun {〈x, y〉 ∣ {x}g{y}} ∧ dom {〈x, y〉 ∣ {x}g{y}} = a)) | 
| 100 | 67, 98, 99 | sylanbrc 645 | 
. . . . . . . 8
⊢ (g:℘1a–1-1-onto→℘1b → {〈x, y〉 ∣ {x}g{y}} Fn
a) | 
| 101 |   | f1ocnv 5300 | 
. . . . . . . . . . . . . . 15
⊢ (g:℘1a–1-1-onto→℘1b → ◡g:℘1b–1-1-onto→℘1a) | 
| 102 |   | f1ofun 5290 | 
. . . . . . . . . . . . . . 15
⊢ (◡g:℘1b–1-1-onto→℘1a → Fun ◡g) | 
| 103 |   | fununiq 5518 | 
. . . . . . . . . . . . . . . . 17
⊢ ((Fun ◡g ∧ {y}◡g{x} ∧ {y}◡g{z}) →
{x} = {z}) | 
| 104 | 103 | 3expib 1154 | 
. . . . . . . . . . . . . . . 16
⊢ (Fun ◡g →
(({y}◡g{x} ∧ {y}◡g{z}) →
{x} = {z})) | 
| 105 |   | brcnv 4893 | 
. . . . . . . . . . . . . . . . 17
⊢ ({y}◡g{x} ↔
{x}g{y}) | 
| 106 |   | brcnv 4893 | 
. . . . . . . . . . . . . . . . 17
⊢ ({y}◡g{z} ↔
{z}g{y}) | 
| 107 | 105, 106 | anbi12i 678 | 
. . . . . . . . . . . . . . . 16
⊢ (({y}◡g{x} ∧ {y}◡g{z}) ↔
({x}g{y} ∧ {z}g{y})) | 
| 108 |   | vex 2863 | 
. . . . . . . . . . . . . . . . 17
⊢ x ∈
V | 
| 109 | 108 | sneqb 3877 | 
. . . . . . . . . . . . . . . 16
⊢ ({x} = {z} ↔
x = z) | 
| 110 | 104, 107,
109 | 3imtr3g 260 | 
. . . . . . . . . . . . . . 15
⊢ (Fun ◡g →
(({x}g{y} ∧ {z}g{y}) →
x = z)) | 
| 111 | 101, 102,
110 | 3syl 18 | 
. . . . . . . . . . . . . 14
⊢ (g:℘1a–1-1-onto→℘1b → (({x}g{y} ∧ {z}g{y}) → x =
z)) | 
| 112 | 111 | alrimivv 1632 | 
. . . . . . . . . . . . 13
⊢ (g:℘1a–1-1-onto→℘1b → ∀x∀z(({x}g{y} ∧ {z}g{y}) → x =
z)) | 
| 113 |   | sneq 3745 | 
. . . . . . . . . . . . . . 15
⊢ (x = z →
{x} = {z}) | 
| 114 | 113 | breq1d 4650 | 
. . . . . . . . . . . . . 14
⊢ (x = z →
({x}g{y} ↔
{z}g{y})) | 
| 115 | 114 | mo4 2237 | 
. . . . . . . . . . . . 13
⊢ (∃*x{x}g{y} ↔ ∀x∀z(({x}g{y} ∧ {z}g{y}) → x =
z)) | 
| 116 | 112, 115 | sylibr 203 | 
. . . . . . . . . . . 12
⊢ (g:℘1a–1-1-onto→℘1b → ∃*x{x}g{y}) | 
| 117 | 116 | alrimiv 1631 | 
. . . . . . . . . . 11
⊢ (g:℘1a–1-1-onto→℘1b → ∀y∃*x{x}g{y}) | 
| 118 |   | funopab 5140 | 
. . . . . . . . . . 11
⊢ (Fun {〈y, x〉 ∣ {x}g{y}} ↔
∀y∃*x{x}g{y}) | 
| 119 | 117, 118 | sylibr 203 | 
. . . . . . . . . 10
⊢ (g:℘1a–1-1-onto→℘1b → Fun {〈y, x〉 ∣ {x}g{y}}) | 
| 120 |   | dmopab 4916 | 
. . . . . . . . . . 11
⊢ dom {〈y, x〉 ∣ {x}g{y}} =
{y ∣
∃x{x}g{y}} | 
| 121 |   | elrn 4897 | 
. . . . . . . . . . . . . . . 16
⊢ ({y} ∈ ran g ↔ ∃z zg{y}) | 
| 122 |   | breldm 4912 | 
. . . . . . . . . . . . . . . . . 18
⊢ (zg{y} → z
∈ dom g) | 
| 123 | 92 | eleq2d 2420 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (g:℘1a–1-1-onto→℘1b → (z
∈ dom g
↔ z ∈ ℘1a)) | 
| 124 |   | elpw1 4145 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (z ∈ ℘1a ↔ ∃w ∈ a z = {w}) | 
| 125 |   | breq1 4643 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ (z = {w} →
(zg{y} ↔
{w}g{y})) | 
| 126 |   | sneq 3745 | 
. . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (x = w →
{x} = {w}) | 
| 127 | 126 | breq1d 4650 | 
. . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (x = w →
({x}g{y} ↔
{w}g{y})) | 
| 128 | 77, 127 | spcev 2947 | 
. . . . . . . . . . . . . . . . . . . . . . 23
⊢ ({w}g{y} → ∃x{x}g{y}) | 
| 129 | 125, 128 | syl6bi 219 | 
. . . . . . . . . . . . . . . . . . . . . 22
⊢ (z = {w} →
(zg{y} →
∃x{x}g{y})) | 
| 130 | 129 | rexlimivw 2735 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ (∃w ∈ a z = {w} →
(zg{y} →
∃x{x}g{y})) | 
| 131 | 124, 130 | sylbi 187 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (z ∈ ℘1a → (zg{y} → ∃x{x}g{y})) | 
| 132 | 123, 131 | syl6bi 219 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (g:℘1a–1-1-onto→℘1b → (z
∈ dom g
→ (zg{y} →
∃x{x}g{y}))) | 
| 133 | 132 | com23 72 | 
. . . . . . . . . . . . . . . . . 18
⊢ (g:℘1a–1-1-onto→℘1b → (zg{y} → (z
∈ dom g
→ ∃x{x}g{y}))) | 
| 134 | 122, 133 | mpdi 38 | 
. . . . . . . . . . . . . . . . 17
⊢ (g:℘1a–1-1-onto→℘1b → (zg{y} → ∃x{x}g{y})) | 
| 135 | 134 | exlimdv 1636 | 
. . . . . . . . . . . . . . . 16
⊢ (g:℘1a–1-1-onto→℘1b → (∃z zg{y} → ∃x{x}g{y})) | 
| 136 | 121, 135 | syl5bi 208 | 
. . . . . . . . . . . . . . 15
⊢ (g:℘1a–1-1-onto→℘1b → ({y}
∈ ran g
→ ∃x{x}g{y})) | 
| 137 |   | brelrn 4961 | 
. . . . . . . . . . . . . . . 16
⊢ ({x}g{y} → {y}
∈ ran g) | 
| 138 | 137 | exlimiv 1634 | 
. . . . . . . . . . . . . . 15
⊢ (∃x{x}g{y} → {y}
∈ ran g) | 
| 139 | 136, 138 | impbid1 194 | 
. . . . . . . . . . . . . 14
⊢ (g:℘1a–1-1-onto→℘1b → ({y}
∈ ran g
↔ ∃x{x}g{y})) | 
| 140 | 73 | eleq2d 2420 | 
. . . . . . . . . . . . . 14
⊢ (g:℘1a–1-1-onto→℘1b → ({y}
∈ ran g
↔ {y} ∈ ℘1b)) | 
| 141 | 139, 140 | bitr3d 246 | 
. . . . . . . . . . . . 13
⊢ (g:℘1a–1-1-onto→℘1b → (∃x{x}g{y} ↔ {y}
∈ ℘1b)) | 
| 142 |   | snelpw1 4147 | 
. . . . . . . . . . . . 13
⊢ ({y} ∈ ℘1b ↔ y ∈ b) | 
| 143 | 141, 142 | syl6bb 252 | 
. . . . . . . . . . . 12
⊢ (g:℘1a–1-1-onto→℘1b → (∃x{x}g{y} ↔ y
∈ b)) | 
| 144 | 143 | eqabcdv 2470 | 
. . . . . . . . . . 11
⊢ (g:℘1a–1-1-onto→℘1b → {y
∣ ∃x{x}g{y}} = b) | 
| 145 | 120, 144 | syl5eq 2397 | 
. . . . . . . . . 10
⊢ (g:℘1a–1-1-onto→℘1b → dom {〈y, x〉 ∣ {x}g{y}} = b) | 
| 146 |   | df-fn 4791 | 
. . . . . . . . . 10
⊢ ({〈y, x〉 ∣ {x}g{y}} Fn
b ↔ (Fun {〈y, x〉 ∣ {x}g{y}} ∧ dom {〈y, x〉 ∣ {x}g{y}} = b)) | 
| 147 | 119, 145,
146 | sylanbrc 645 | 
. . . . . . . . 9
⊢ (g:℘1a–1-1-onto→℘1b → {〈y, x〉 ∣ {x}g{y}} Fn
b) | 
| 148 |   | cnvopab 5031 | 
. . . . . . . . . 10
⊢ ◡{〈x, y〉 ∣ {x}g{y}} = {〈y, x〉 ∣ {x}g{y}} | 
| 149 | 148 | fneq1i 5179 | 
. . . . . . . . 9
⊢ (◡{〈x, y〉 ∣ {x}g{y}} Fn b ↔
{〈y,
x〉 ∣ {x}g{y}} Fn
b) | 
| 150 | 147, 149 | sylibr 203 | 
. . . . . . . 8
⊢ (g:℘1a–1-1-onto→℘1b → ◡{〈x, y〉 ∣ {x}g{y}} Fn b) | 
| 151 |   | dff1o4 5295 | 
. . . . . . . 8
⊢ ({〈x, y〉 ∣ {x}g{y}}:a–1-1-onto→b ↔
({〈x,
y〉 ∣ {x}g{y}} Fn
a ∧ ◡{〈x, y〉 ∣ {x}g{y}} Fn b)) | 
| 152 | 100, 150,
151 | sylanbrc 645 | 
. . . . . . 7
⊢ (g:℘1a–1-1-onto→℘1b → {〈x, y〉 ∣ {x}g{y}}:a–1-1-onto→b) | 
| 153 |   | enpw1lem1 6062 | 
. . . . . . . 8
⊢ {〈x, y〉 ∣ {x}g{y}} ∈ V | 
| 154 | 153 | f1oen 6034 | 
. . . . . . 7
⊢ ({〈x, y〉 ∣ {x}g{y}}:a–1-1-onto→b →
a ≈ b) | 
| 155 | 152, 154 | syl 15 | 
. . . . . 6
⊢ (g:℘1a–1-1-onto→℘1b → a
≈ b) | 
| 156 | 155 | exlimiv 1634 | 
. . . . 5
⊢ (∃g g:℘1a–1-1-onto→℘1b → a
≈ b) | 
| 157 | 52, 156 | sylbi 187 | 
. . . 4
⊢ (℘1a ≈ ℘1b → a
≈ b) | 
| 158 | 51, 157 | impbii 180 | 
. . 3
⊢ (a ≈ b
↔ ℘1a ≈ ℘1b) | 
| 159 | 10, 14, 158 | vtocl2g 2919 | 
. 2
⊢ ((A ∈ V ∧ B ∈ V) → (A
≈ B ↔ ℘1A ≈ ℘1B)) | 
| 160 | 1, 6, 159 | pm5.21nii 342 | 
1
⊢ (A ≈ B
↔ ℘1A ≈ ℘1B) |