Step |
Hyp |
Ref |
Expression |
1 |
|
dfrn2 |
|- ran R = { y | E. x x R y } |
2 |
|
nfopab2 |
|- F/_ y { <. x , y >. | ph } |
3 |
2
|
nfeq2 |
|- F/ y R = { <. x , y >. | ph } |
4 |
|
nfopab1 |
|- F/_ x { <. x , y >. | ph } |
5 |
4
|
nfeq2 |
|- F/ x R = { <. x , y >. | ph } |
6 |
|
df-br |
|- ( x R y <-> <. x , y >. e. R ) |
7 |
|
eleq2 |
|- ( R = { <. x , y >. | ph } -> ( <. x , y >. e. R <-> <. x , y >. e. { <. x , y >. | ph } ) ) |
8 |
|
opabidw |
|- ( <. x , y >. e. { <. x , y >. | ph } <-> ph ) |
9 |
7 8
|
bitrdi |
|- ( R = { <. x , y >. | ph } -> ( <. x , y >. e. R <-> ph ) ) |
10 |
6 9
|
syl5bb |
|- ( R = { <. x , y >. | ph } -> ( x R y <-> ph ) ) |
11 |
5 10
|
exbid |
|- ( R = { <. x , y >. | ph } -> ( E. x x R y <-> E. x ph ) ) |
12 |
3 11
|
abbid |
|- ( R = { <. x , y >. | ph } -> { y | E. x x R y } = { y | E. x ph } ) |
13 |
1 12
|
syl5eq |
|- ( R = { <. x , y >. | ph } -> ran R = { y | E. x ph } ) |