Metamath Proof Explorer


Theorem elmapex

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 ) )

Proof

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 ) )