Step |
Hyp |
Ref |
Expression |
1 |
|
brabgaf.0 |
|- F/ x ps |
2 |
|
brabgaf.1 |
|- ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) |
3 |
|
brabgaf.2 |
|- R = { <. x , y >. | ph } |
4 |
|
df-br |
|- ( A R B <-> <. A , B >. e. R ) |
5 |
3
|
eleq2i |
|- ( <. A , B >. e. R <-> <. A , B >. e. { <. x , y >. | ph } ) |
6 |
4 5
|
bitri |
|- ( A R B <-> <. A , B >. e. { <. x , y >. | ph } ) |
7 |
|
elopab |
|- ( <. A , B >. e. { <. x , y >. | ph } <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) ) |
8 |
|
elisset |
|- ( A e. V -> E. x x = A ) |
9 |
|
elisset |
|- ( B e. W -> E. y y = B ) |
10 |
|
exdistrv |
|- ( E. x E. y ( x = A /\ y = B ) <-> ( E. x x = A /\ E. y y = B ) ) |
11 |
|
nfe1 |
|- F/ x E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) |
12 |
11 1
|
nfbi |
|- F/ x ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) |
13 |
|
nfe1 |
|- F/ y E. y ( <. A , B >. = <. x , y >. /\ ph ) |
14 |
13
|
nfex |
|- F/ y E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) |
15 |
|
nfv |
|- F/ y ps |
16 |
14 15
|
nfbi |
|- F/ y ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) |
17 |
|
opeq12 |
|- ( ( x = A /\ y = B ) -> <. x , y >. = <. A , B >. ) |
18 |
|
copsexgw |
|- ( <. A , B >. = <. x , y >. -> ( ph <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) ) ) |
19 |
18
|
eqcoms |
|- ( <. x , y >. = <. A , B >. -> ( ph <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) ) ) |
20 |
17 19
|
syl |
|- ( ( x = A /\ y = B ) -> ( ph <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) ) ) |
21 |
20 2
|
bitr3d |
|- ( ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) |
22 |
16 21
|
exlimi |
|- ( E. y ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) |
23 |
12 22
|
exlimi |
|- ( E. x E. y ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) |
24 |
10 23
|
sylbir |
|- ( ( E. x x = A /\ E. y y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) |
25 |
8 9 24
|
syl2an |
|- ( ( A e. V /\ B e. W ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) |
26 |
7 25
|
syl5bb |
|- ( ( A e. V /\ B e. W ) -> ( <. A , B >. e. { <. x , y >. | ph } <-> ps ) ) |
27 |
6 26
|
syl5bb |
|- ( ( A e. V /\ B e. W ) -> ( A R B <-> ps ) ) |