| Step |
Hyp |
Ref |
Expression |
| 1 |
|
marypha2lem.t |
|- T = U_ x e. A ( { x } X. ( F ` x ) ) |
| 2 |
|
iunss |
|- ( U_ x e. A ( { x } X. ( F ` x ) ) C_ ( A X. U. ran F ) <-> A. x e. A ( { x } X. ( F ` x ) ) C_ ( A X. U. ran F ) ) |
| 3 |
|
snssi |
|- ( x e. A -> { x } C_ A ) |
| 4 |
|
fvssunirn |
|- ( F ` x ) C_ U. ran F |
| 5 |
|
xpss12 |
|- ( ( { x } C_ A /\ ( F ` x ) C_ U. ran F ) -> ( { x } X. ( F ` x ) ) C_ ( A X. U. ran F ) ) |
| 6 |
3 4 5
|
sylancl |
|- ( x e. A -> ( { x } X. ( F ` x ) ) C_ ( A X. U. ran F ) ) |
| 7 |
2 6
|
mprgbir |
|- U_ x e. A ( { x } X. ( F ` x ) ) C_ ( A X. U. ran F ) |
| 8 |
1 7
|
eqsstri |
|- T C_ ( A X. U. ran F ) |