Description: Membership in a range. (Contributed by Scott Fenton, 2-Feb-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | elrn2g | |- ( A e. V -> ( A e. ran B <-> E. x <. x , A >. e. B ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | opeq2 | |- ( y = A -> <. x , y >. = <. x , A >. ) |
|
2 | 1 | eleq1d | |- ( y = A -> ( <. x , y >. e. B <-> <. x , A >. e. B ) ) |
3 | 2 | exbidv | |- ( y = A -> ( E. x <. x , y >. e. B <-> E. x <. x , A >. e. B ) ) |
4 | dfrn3 | |- ran B = { y | E. x <. x , y >. e. B } |
|
5 | 3 4 | elab2g | |- ( A e. V -> ( A e. ran B <-> E. x <. x , A >. e. B ) ) |