Step |
Hyp |
Ref |
Expression |
1 |
|
breq1 |
|- ( x = A -> ( x Image R y <-> A Image R y ) ) |
2 |
|
imaeq2 |
|- ( x = A -> ( R " x ) = ( R " A ) ) |
3 |
2
|
eqeq2d |
|- ( x = A -> ( y = ( R " x ) <-> y = ( R " A ) ) ) |
4 |
1 3
|
bibi12d |
|- ( x = A -> ( ( x Image R y <-> y = ( R " x ) ) <-> ( A Image R y <-> y = ( R " A ) ) ) ) |
5 |
|
breq2 |
|- ( y = B -> ( A Image R y <-> A Image R B ) ) |
6 |
|
eqeq1 |
|- ( y = B -> ( y = ( R " A ) <-> B = ( R " A ) ) ) |
7 |
5 6
|
bibi12d |
|- ( y = B -> ( ( A Image R y <-> y = ( R " A ) ) <-> ( A Image R B <-> B = ( R " A ) ) ) ) |
8 |
|
vex |
|- x e. _V |
9 |
|
vex |
|- y e. _V |
10 |
8 9
|
brimage |
|- ( x Image R y <-> y = ( R " x ) ) |
11 |
4 7 10
|
vtocl2g |
|- ( ( A e. V /\ B e. W ) -> ( A Image R B <-> B = ( R " A ) ) ) |