Metamath Proof Explorer


Definition df-coels

Description: Define the class of coelements on the class A , see also the alternate definition dfcoels . Possible definitions are the special cases of dfcoss3 and dfcoss4 . (Contributed by Peter Mazsa, 20-Nov-2019)

Ref Expression
Assertion df-coels A = E -1 A

Detailed syntax breakdown

Step Hyp Ref Expression
0 cA class A
1 0 ccoels class A
2 cep class E
3 2 ccnv class E -1
4 3 0 cres class E -1 A
5 4 ccoss class E -1 A
6 1 5 wceq wff A = E -1 A