| Step |
Hyp |
Ref |
Expression |
| 1 |
|
gdlop1fv.1 |
|- ( ph -> A e. V ) |
| 2 |
|
gdlop1fv.2 |
|- ( ph -> B e. W ) |
| 3 |
1
|
elexd |
|- ( ph -> A e. _V ) |
| 4 |
2
|
elexd |
|- ( ph -> B e. _V ) |
| 5 |
|
prex |
|- { A , B } e. _V |
| 6 |
5
|
a1i |
|- ( ph -> { A , B } e. _V ) |
| 7 |
|
preq1 |
|- ( A = x -> { A , y } = { x , y } ) |
| 8 |
7
|
adantl |
|- ( ( ph /\ A = x ) -> { A , y } = { x , y } ) |
| 9 |
|
preq2 |
|- ( B = y -> { A , B } = { A , y } ) |
| 10 |
9
|
adantl |
|- ( ( ph /\ B = y ) -> { A , B } = { A , y } ) |
| 11 |
|
df-gdlop1 |
|- ~F1 = ( x e. _V , y e. _V |-> { x , y } ) |
| 12 |
3 4 6 8 10 11
|
mpofvop2d |
|- ( ph -> ( ~F1 ` <. A , B >. ) = { A , B } ) |