Detailed syntax breakdown of Definition df-ce
| Step | Hyp | Ref
 | Expression | 
| 1 |   | cce 6097 | 
. 2
class 
↑c | 
| 2 |   | vn | 
. . 3
setvar n | 
| 3 |   | vm | 
. . 3
setvar m | 
| 4 |   | cncs 6089 | 
. . 3
class  NC | 
| 5 |   | va | 
. . . . . . . . . 10
setvar a | 
| 6 | 5 | cv 1641 | 
. . . . . . . . 9
class a | 
| 7 | 6 | cpw1 4136 | 
. . . . . . . 8
class ℘1a | 
| 8 | 2 | cv 1641 | 
. . . . . . . 8
class n | 
| 9 | 7, 8 | wcel 1710 | 
. . . . . . 7
wff ℘1a ∈ n | 
| 10 |   | vb | 
. . . . . . . . . 10
setvar b | 
| 11 | 10 | cv 1641 | 
. . . . . . . . 9
class b | 
| 12 | 11 | cpw1 4136 | 
. . . . . . . 8
class ℘1b | 
| 13 | 3 | cv 1641 | 
. . . . . . . 8
class m | 
| 14 | 12, 13 | wcel 1710 | 
. . . . . . 7
wff ℘1b ∈ m | 
| 15 |   | vg | 
. . . . . . . . 9
setvar g | 
| 16 | 15 | cv 1641 | 
. . . . . . . 8
class g | 
| 17 |   | cmap 6000 | 
. . . . . . . . 9
class 
↑m | 
| 18 | 6, 11, 17 | co 5526 | 
. . . . . . . 8
class (a ↑m b) | 
| 19 |   | cen 6029 | 
. . . . . . . 8
class  ≈ | 
| 20 | 16, 18, 19 | wbr 4640 | 
. . . . . . 7
wff g
≈ (a ↑m
b) | 
| 21 | 9, 14, 20 | w3a 934 | 
. . . . . 6
wff (℘1a ∈ n ∧ ℘1b ∈ m ∧ g ≈ (a
↑m b)) | 
| 22 | 21, 10 | wex 1541 | 
. . . . 5
wff ∃b(℘1a ∈ n ∧ ℘1b ∈ m ∧ g ≈ (a
↑m b)) | 
| 23 | 22, 5 | wex 1541 | 
. . . 4
wff ∃a∃b(℘1a ∈ n ∧ ℘1b ∈ m ∧ g ≈ (a
↑m b)) | 
| 24 | 23, 15 | cab 2339 | 
. . 3
class {g ∣ ∃a∃b(℘1a ∈ n ∧ ℘1b ∈ m ∧ g ≈ (a
↑m b))} | 
| 25 | 2, 3, 4, 4, 24 | cmpt2 5654 | 
. 2
class (n ∈ NC , m ∈ NC ↦ {g ∣ ∃a∃b(℘1a ∈ n ∧ ℘1b ∈ m ∧ g ≈ (a
↑m b))}) | 
| 26 | 1, 25 | wceq 1642 | 
1
wff  ↑c = (n ∈ NC , m ∈ NC ↦ {g ∣ ∃a∃b(℘1a ∈ n ∧ ℘1b ∈ m ∧ g ≈ (a
↑m b))}) |