Metamath Proof Explorer


Definition df-prpr

Description: Define the function which maps a set v to the set of proper unordered pairs consisting of exactly two (different) elements of the set v . (Contributed by AV, 29-Apr-2023)

Ref Expression
Assertion df-prpr PrPairs=vVp|avbvabp=ab

Detailed syntax breakdown

Step Hyp Ref Expression
0 cprpr classPrPairs
1 vv setvarv
2 cvv classV
3 vp setvarp
4 va setvara
5 1 cv setvarv
6 vb setvarb
7 4 cv setvara
8 6 cv setvarb
9 7 8 wne wffab
10 3 cv setvarp
11 7 8 cpr classab
12 10 11 wceq wffp=ab
13 9 12 wa wffabp=ab
14 13 6 5 wrex wffbvabp=ab
15 14 4 5 wrex wffavbvabp=ab
16 15 3 cab classp|avbvabp=ab
17 1 2 16 cmpt classvVp|avbvabp=ab
18 0 17 wceq wffPrPairs=vVp|avbvabp=ab