Metamath Proof Explorer


Definition df-coll

Description: Define the collection operation. This is similar to the image set operation " , but it uses Scott's trick to ensure the output is always a set. (Contributed by Rohan Ridenour, 11-Aug-2023)

Ref Expression
Assertion df-coll FCollA=xAScottFx

Detailed syntax breakdown

Step Hyp Ref Expression
0 cF classF
1 cA classA
2 1 0 ccoll classFCollA
3 vx setvarx
4 3 cv setvarx
5 4 csn classx
6 0 5 cima classFx
7 6 cscott classScottFx
8 3 1 7 ciun classxAScottFx
9 2 8 wceq wffFCollA=xAScottFx