| Step | Hyp | Ref
 | Expression | 
| 1 |   | elin 3220 | 
. . . . . 6
⊢ (f ∈ ( Funs ∩ (◡Image1st “ {A})) ↔ (f
∈ Funs ∧ f ∈ (◡Image1st “ {A}))) | 
| 2 |   | vex 2863 | 
. . . . . . . 8
⊢ f ∈
V | 
| 3 | 2 | elfuns 5830 | 
. . . . . . 7
⊢ (f ∈ Funs ↔ Fun f) | 
| 4 |   | elimasn 5020 | 
. . . . . . . 8
⊢ (f ∈ (◡Image1st “ {A}) ↔ 〈A, f〉 ∈ ◡Image1st ) | 
| 5 |   | df-br 4641 | 
. . . . . . . 8
⊢ (A◡Image1st f ↔ 〈A, f〉 ∈ ◡Image1st ) | 
| 6 |   | brcnv 4893 | 
. . . . . . . . 9
⊢ (A◡Image1st f ↔ fImage1st A) | 
| 7 |   | mapexi.1 | 
. . . . . . . . . . 11
⊢ A ∈
V | 
| 8 | 2, 7 | brimage 5794 | 
. . . . . . . . . 10
⊢ (fImage1st A ↔ A =
(1st “ f)) | 
| 9 |   | dfdm4 5508 | 
. . . . . . . . . . 11
⊢ dom f = (1st “ f) | 
| 10 | 9 | eqeq2i 2363 | 
. . . . . . . . . 10
⊢ (A = dom f ↔
A = (1st “ f)) | 
| 11 |   | eqcom 2355 | 
. . . . . . . . . 10
⊢ (A = dom f ↔
dom f = A) | 
| 12 | 8, 10, 11 | 3bitr2i 264 | 
. . . . . . . . 9
⊢ (fImage1st A ↔ dom f =
A) | 
| 13 | 6, 12 | bitri 240 | 
. . . . . . . 8
⊢ (A◡Image1st f ↔ dom f =
A) | 
| 14 | 4, 5, 13 | 3bitr2i 264 | 
. . . . . . 7
⊢ (f ∈ (◡Image1st “ {A}) ↔ dom f
= A) | 
| 15 | 3, 14 | anbi12i 678 | 
. . . . . 6
⊢ ((f ∈ Funs ∧ f ∈ (◡Image1st “ {A})) ↔ (Fun f ∧ dom f = A)) | 
| 16 | 1, 15 | bitri 240 | 
. . . . 5
⊢ (f ∈ ( Funs ∩ (◡Image1st “ {A})) ↔ (Fun f ∧ dom f = A)) | 
| 17 |   | vex 2863 | 
. . . . . . . . . 10
⊢ x ∈
V | 
| 18 | 2, 17 | brimage 5794 | 
. . . . . . . . 9
⊢ (fImage2nd x ↔ x =
(2nd “ f)) | 
| 19 |   | brcnv 4893 | 
. . . . . . . . 9
⊢ (x◡Image2nd f ↔ fImage2nd x) | 
| 20 |   | dfrn5 5509 | 
. . . . . . . . . 10
⊢ ran f = (2nd “ f) | 
| 21 | 20 | eqeq2i 2363 | 
. . . . . . . . 9
⊢ (x = ran f ↔
x = (2nd “ f)) | 
| 22 | 18, 19, 21 | 3bitr4i 268 | 
. . . . . . . 8
⊢ (x◡Image2nd f ↔ x = ran
f) | 
| 23 | 22 | rexbii 2640 | 
. . . . . . 7
⊢ (∃x ∈ ℘ Bx◡Image2nd f ↔ ∃x ∈ ℘ Bx = ran
f) | 
| 24 |   | elima 4755 | 
. . . . . . 7
⊢ (f ∈ (◡Image2nd “ ℘B) ↔
∃x ∈ ℘ Bx◡Image2nd f) | 
| 25 |   | risset 2662 | 
. . . . . . 7
⊢ (ran f ∈ ℘B ↔
∃x ∈ ℘ Bx = ran
f) | 
| 26 | 23, 24, 25 | 3bitr4i 268 | 
. . . . . 6
⊢ (f ∈ (◡Image2nd “ ℘B) ↔
ran f ∈
℘B) | 
| 27 | 2 | rnex 5108 | 
. . . . . . 7
⊢ ran f ∈
V | 
| 28 | 27 | elpw 3729 | 
. . . . . 6
⊢ (ran f ∈ ℘B ↔ ran
f ⊆
B) | 
| 29 | 26, 28 | bitri 240 | 
. . . . 5
⊢ (f ∈ (◡Image2nd “ ℘B) ↔
ran f ⊆
B) | 
| 30 | 16, 29 | anbi12i 678 | 
. . . 4
⊢ ((f ∈ ( Funs ∩ (◡Image1st “ {A})) ∧ f ∈ (◡Image2nd “ ℘B)) ↔
((Fun f ∧
dom f = A) ∧ ran f ⊆ B)) | 
| 31 |   | elin 3220 | 
. . . 4
⊢ (f ∈ (( Funs ∩ (◡Image1st “ {A})) ∩ (◡Image2nd “ ℘B)) ↔
(f ∈ (
Funs ∩ (◡Image1st “ {A})) ∧ f ∈ (◡Image2nd “ ℘B))) | 
| 32 |   | df-f 4792 | 
. . . . 5
⊢ (f:A–→B
↔ (f Fn A ∧ ran f ⊆ B)) | 
| 33 |   | df-fn 4791 | 
. . . . . 6
⊢ (f Fn A ↔
(Fun f ∧
dom f = A)) | 
| 34 | 33 | anbi1i 676 | 
. . . . 5
⊢ ((f Fn A ∧ ran f ⊆ B) ↔
((Fun f ∧
dom f = A) ∧ ran f ⊆ B)) | 
| 35 | 32, 34 | bitri 240 | 
. . . 4
⊢ (f:A–→B
↔ ((Fun f ∧ dom f =
A) ∧ ran
f ⊆
B)) | 
| 36 | 30, 31, 35 | 3bitr4i 268 | 
. . 3
⊢ (f ∈ (( Funs ∩ (◡Image1st “ {A})) ∩ (◡Image2nd “ ℘B)) ↔
f:A–→B) | 
| 37 | 36 | eqabi 2465 | 
. 2
⊢ (( Funs ∩ (◡Image1st “ {A})) ∩ (◡Image2nd “ ℘B)) =
{f ∣
f:A–→B} | 
| 38 |   | funsex 5829 | 
. . . 4
⊢  Funs ∈
V | 
| 39 |   | 1stex 4740 | 
. . . . . . 7
⊢ 1st
∈ V | 
| 40 | 39 | imageex 5802 | 
. . . . . 6
⊢ Image1st
∈ V | 
| 41 | 40 | cnvex 5103 | 
. . . . 5
⊢ ◡Image1st ∈ V | 
| 42 |   | snex 4112 | 
. . . . 5
⊢ {A} ∈
V | 
| 43 | 41, 42 | imaex 4748 | 
. . . 4
⊢ (◡Image1st “ {A}) ∈
V | 
| 44 | 38, 43 | inex 4106 | 
. . 3
⊢ ( Funs ∩ (◡Image1st “ {A})) ∈
V | 
| 45 |   | 2ndex 5113 | 
. . . . . 6
⊢ 2nd
∈ V | 
| 46 | 45 | imageex 5802 | 
. . . . 5
⊢ Image2nd
∈ V | 
| 47 | 46 | cnvex 5103 | 
. . . 4
⊢ ◡Image2nd ∈ V | 
| 48 |   | mapexi.2 | 
. . . . 5
⊢ B ∈
V | 
| 49 | 48 | pwex 4330 | 
. . . 4
⊢ ℘B ∈ V | 
| 50 | 47, 49 | imaex 4748 | 
. . 3
⊢ (◡Image2nd “ ℘B) ∈ V | 
| 51 | 44, 50 | inex 4106 | 
. 2
⊢ (( Funs ∩ (◡Image1st “ {A})) ∩ (◡Image2nd “ ℘B)) ∈ V | 
| 52 | 37, 51 | eqeltrri 2424 | 
1
⊢ {f ∣ f:A–→B}
∈ V |