| Step |
Hyp |
Ref |
Expression |
| 1 |
|
nfa1 |
|- F/ x A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) |
| 2 |
|
nfe1 |
|- F/ x E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) |
| 3 |
|
nfv |
|- F/ x ps |
| 4 |
2 3
|
nfbi |
|- F/ x ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) |
| 5 |
|
nfa2 |
|- F/ y A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) |
| 6 |
|
nfe1 |
|- F/ y E. y ( <. A , B >. = <. x , y >. /\ ph ) |
| 7 |
6
|
nfex |
|- F/ y E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) |
| 8 |
|
nfv |
|- F/ y ps |
| 9 |
7 8
|
nfbi |
|- F/ y ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) |
| 10 |
|
opeq12 |
|- ( ( x = A /\ y = B ) -> <. x , y >. = <. A , B >. ) |
| 11 |
|
copsexgw |
|- ( <. A , B >. = <. x , y >. -> ( ph <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) ) ) |
| 12 |
11
|
eqcoms |
|- ( <. x , y >. = <. A , B >. -> ( ph <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) ) ) |
| 13 |
10 12
|
syl |
|- ( ( x = A /\ y = B ) -> ( ph <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) ) ) |
| 14 |
13
|
adantl |
|- ( ( A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) /\ ( x = A /\ y = B ) ) -> ( ph <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) ) ) |
| 15 |
|
2sp |
|- ( A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) -> ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) ) |
| 16 |
15
|
imp |
|- ( ( A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) /\ ( x = A /\ y = B ) ) -> ( ph <-> ps ) ) |
| 17 |
14 16
|
bitr3d |
|- ( ( A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) /\ ( x = A /\ y = B ) ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) |
| 18 |
17
|
ex |
|- ( A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) -> ( ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) ) |
| 19 |
5 9 18
|
exlimd |
|- ( A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) -> ( E. y ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) ) |
| 20 |
1 4 19
|
exlimd |
|- ( A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) -> ( E. x E. y ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) ) |
| 21 |
|
elisset |
|- ( A e. V -> E. x x = A ) |
| 22 |
|
elisset |
|- ( B e. W -> E. y y = B ) |
| 23 |
21 22
|
anim12i |
|- ( ( A e. V /\ B e. W ) -> ( E. x x = A /\ E. y y = B ) ) |
| 24 |
|
exdistrv |
|- ( E. x E. y ( x = A /\ y = B ) <-> ( E. x x = A /\ E. y y = B ) ) |
| 25 |
23 24
|
sylibr |
|- ( ( A e. V /\ B e. W ) -> E. x E. y ( x = A /\ y = B ) ) |
| 26 |
20 25
|
impel |
|- ( ( A. x A. y ( ( x = A /\ y = B ) -> ( ph <-> ps ) ) /\ ( A e. V /\ B e. W ) ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ph ) <-> ps ) ) |