Description: Conditional operator existence. (Contributed by NM, 21-Mar-2011) (Proof shortened by BJ, 1-Sep-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | ifexg | |- ( ( A e. V /\ B e. W ) -> if ( ph , A , B ) e. _V ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elex | |- ( A e. V -> A e. _V ) |
|
2 | elex | |- ( B e. W -> B e. _V ) |
|
3 | ifcl | |- ( ( A e. _V /\ B e. _V ) -> if ( ph , A , B ) e. _V ) |
|
4 | 1 2 3 | syl2an | |- ( ( A e. V /\ B e. W ) -> if ( ph , A , B ) e. _V ) |