Description: Eliminate antecedent for mapping theorems: domain can be taken to be a set. (Contributed by Stefan O'Rear, 8-Oct-2014)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | elmapex | |- ( A e. ( B ^m C ) -> ( B e. _V /\ C e. _V ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | n0i | |- ( A e. ( B ^m C ) -> -. ( B ^m C ) = (/) ) |
|
| 2 | fnmap | |- ^m Fn ( _V X. _V ) |
|
| 3 | 2 | fndmi | |- dom ^m = ( _V X. _V ) |
| 4 | 3 | ndmov | |- ( -. ( B e. _V /\ C e. _V ) -> ( B ^m C ) = (/) ) |
| 5 | 1 4 | nsyl2 | |- ( A e. ( B ^m C ) -> ( B e. _V /\ C e. _V ) ) |