Metamath Proof Explorer


Theorem sprval

Description: The set of all unordered pairs over a given set V . (Contributed by AV, 21-Nov-2021)

Ref Expression
Assertion sprval VWPairsV=p|aVbVp=ab

Proof

Step Hyp Ref Expression
1 df-spr Pairs=vVp|avbvp=ab
2 1 a1i VWPairs=vVp|avbvp=ab
3 id v=Vv=V
4 rexeq v=Vbvp=abbVp=ab
5 3 4 rexeqbidv v=Vavbvp=abaVbVp=ab
6 5 adantl VWv=Vavbvp=abaVbVp=ab
7 6 abbidv VWv=Vp|avbvp=ab=p|aVbVp=ab
8 elex VWVV
9 zfpair2 abV
10 eueq abV∃!pp=ab
11 9 10 mpbi ∃!pp=ab
12 euabex ∃!pp=abp|p=abV
13 11 12 mp1i VWp|p=abV
14 13 ralrimivw VWbVp|p=abV
15 abrexex2g VWbVp|p=abVp|bVp=abV
16 14 15 mpdan VWp|bVp=abV
17 16 ralrimivw VWaVp|bVp=abV
18 abrexex2g VWaVp|bVp=abVp|aVbVp=abV
19 17 18 mpdan VWp|aVbVp=abV
20 2 7 8 19 fvmptd VWPairsV=p|aVbVp=ab