Detailed syntax breakdown of Definition df-ins4
| Step | Hyp | Ref
 | Expression | 
| 1 |   | cA | 
. . 3
class A | 
| 2 | 1 | cins4 5756 | 
. 2
class  Ins4
A | 
| 3 |   | c1st 4718 | 
. . . . 5
class 1st | 
| 4 |   | c2nd 4784 | 
. . . . . . 7
class 2nd | 
| 5 | 3, 4 | ccom 4722 | 
. . . . . 6
class (1st ∘ 2nd ) | 
| 6 | 5, 4 | ccom 4722 | 
. . . . . 6
class ((1st ∘ 2nd ) ∘ 2nd ) | 
| 7 | 5, 6 | ctxp 5736 | 
. . . . 5
class ((1st ∘ 2nd ) ⊗ ((1st ∘ 2nd ) ∘ 2nd )) | 
| 8 | 3, 7 | ctxp 5736 | 
. . . 4
class (1st ⊗
((1st ∘ 2nd ) ⊗
((1st ∘ 2nd ) ∘ 2nd ))) | 
| 9 | 8 | ccnv 4772 | 
. . 3
class ◡(1st ⊗ ((1st
∘ 2nd ) ⊗ ((1st
∘ 2nd ) ∘ 2nd ))) | 
| 10 | 9, 1 | cima 4723 | 
. 2
class (◡(1st ⊗ ((1st
∘ 2nd ) ⊗ ((1st
∘ 2nd ) ∘ 2nd ))) “ A) | 
| 11 | 2, 10 | wceq 1642 | 
1
wff  Ins4
A = (◡(1st ⊗ ((1st
∘ 2nd ) ⊗ ((1st
∘ 2nd ) ∘ 2nd ))) “ A) |