Step |
Hyp |
Ref |
Expression |
1 |
|
fnbrovb |
|- ( ( F Fn ( A X. B ) /\ ( C e. A /\ D e. B ) ) -> ( ( C F D ) = R <-> <. C , D >. F R ) ) |
2 |
|
df-br |
|- ( <. C , D >. F R <-> <. <. C , D >. , R >. e. F ) |
3 |
2
|
a1i |
|- ( ( F Fn ( A X. B ) /\ ( C e. A /\ D e. B ) ) -> ( <. C , D >. F R <-> <. <. C , D >. , R >. e. F ) ) |
4 |
|
df-ot |
|- <. C , D , R >. = <. <. C , D >. , R >. |
5 |
4
|
eqcomi |
|- <. <. C , D >. , R >. = <. C , D , R >. |
6 |
5
|
eleq1i |
|- ( <. <. C , D >. , R >. e. F <-> <. C , D , R >. e. F ) |
7 |
6
|
a1i |
|- ( ( F Fn ( A X. B ) /\ ( C e. A /\ D e. B ) ) -> ( <. <. C , D >. , R >. e. F <-> <. C , D , R >. e. F ) ) |
8 |
1 3 7
|
3bitrd |
|- ( ( F Fn ( A X. B ) /\ ( C e. A /\ D e. B ) ) -> ( ( C F D ) = R <-> <. C , D , R >. e. F ) ) |
9 |
8
|
3impb |
|- ( ( F Fn ( A X. B ) /\ C e. A /\ D e. B ) -> ( ( C F D ) = R <-> <. C , D , R >. e. F ) ) |