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| Mirrors > Home > NFE Home > Th. List > df-cok | GIF version | ||
| Description: Define the Kuratowski composition operator. (Contributed by SF, 12-Jan-2015.) | 
| Ref | Expression | 
|---|---|
| df-cok | ⊢ (A ∘k B) = (( Ins2k A ∩ Ins3k ◡kB) “k V) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cA | . . 3 class A | |
| 2 | cB | . . 3 class B | |
| 3 | 1, 2 | ccomk 4181 | . 2 class (A ∘k B) | 
| 4 | 1 | cins2k 4177 | . . . 4 class Ins2k A | 
| 5 | 2 | ccnvk 4176 | . . . . 5 class ◡kB | 
| 6 | 5 | cins3k 4178 | . . . 4 class Ins3k ◡kB | 
| 7 | 4, 6 | cin 3209 | . . 3 class ( Ins2k A ∩ Ins3k ◡kB) | 
| 8 | cvv 2860 | . . 3 class V | |
| 9 | 7, 8 | cimak 4180 | . 2 class (( Ins2k A ∩ Ins3k ◡kB) “k V) | 
| 10 | 3, 9 | wceq 1642 | 1 wff (A ∘k B) = (( Ins2k A ∩ Ins3k ◡kB) “k V) | 
| Colors of variables: wff setvar class | 
| This definition is referenced by: cokeq1 4231 cokeq2 4232 opkelcokg 4262 cokrelk 4285 cokexg 4310 | 
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