Metamath Proof Explorer


Theorem vvdifopab

Description: Ordered-pair class abstraction defined by a negation. (Contributed by Peter Mazsa, 25-Jun-2019)

Ref Expression
Assertion vvdifopab V×Vxy|φ=xy|¬φ

Proof

Step Hyp Ref Expression
1 opabidw xyxy|φφ
2 1 notbii ¬xyxy|φ¬φ
3 opelvvdif xVyVxyV×Vxy|φ¬xyxy|φ
4 3 el2v xyV×Vxy|φ¬xyxy|φ
5 opabidw xyxy|¬φ¬φ
6 2 4 5 3bitr4i xyV×Vxy|φxyxy|¬φ
7 6 gen2 xyxyV×Vxy|φxyxy|¬φ
8 relxp RelV×V
9 reldif RelV×VRelV×Vxy|φ
10 8 9 ax-mp RelV×Vxy|φ
11 relopabv Relxy|¬φ
12 nfcv _xV×V
13 nfopab1 _xxy|φ
14 12 13 nfdif _xV×Vxy|φ
15 nfopab1 _xxy|¬φ
16 nfcv _yV×V
17 nfopab2 _yxy|φ
18 16 17 nfdif _yV×Vxy|φ
19 nfopab2 _yxy|¬φ
20 14 15 18 19 eqrelf RelV×Vxy|φRelxy|¬φV×Vxy|φ=xy|¬φxyxyV×Vxy|φxyxy|¬φ
21 10 11 20 mp2an V×Vxy|φ=xy|¬φxyxyV×Vxy|φxyxy|¬φ
22 7 21 mpbir V×Vxy|φ=xy|¬φ