Step |
Hyp |
Ref |
Expression |
1 |
|
poleloe |
|- ( C e. X -> ( B ( R u. _I ) C <-> ( B R C \/ B = C ) ) ) |
2 |
1
|
3ad2ant3 |
|- ( ( A e. X /\ B e. X /\ C e. X ) -> ( B ( R u. _I ) C <-> ( B R C \/ B = C ) ) ) |
3 |
2
|
adantl |
|- ( ( R Po X /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( B ( R u. _I ) C <-> ( B R C \/ B = C ) ) ) |
4 |
3
|
anbi2d |
|- ( ( R Po X /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A R B /\ B ( R u. _I ) C ) <-> ( A R B /\ ( B R C \/ B = C ) ) ) ) |
5 |
|
potr |
|- ( ( R Po X /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A R B /\ B R C ) -> A R C ) ) |
6 |
5
|
com12 |
|- ( ( A R B /\ B R C ) -> ( ( R Po X /\ ( A e. X /\ B e. X /\ C e. X ) ) -> A R C ) ) |
7 |
|
breq2 |
|- ( B = C -> ( A R B <-> A R C ) ) |
8 |
7
|
biimpac |
|- ( ( A R B /\ B = C ) -> A R C ) |
9 |
8
|
a1d |
|- ( ( A R B /\ B = C ) -> ( ( R Po X /\ ( A e. X /\ B e. X /\ C e. X ) ) -> A R C ) ) |
10 |
6 9
|
jaodan |
|- ( ( A R B /\ ( B R C \/ B = C ) ) -> ( ( R Po X /\ ( A e. X /\ B e. X /\ C e. X ) ) -> A R C ) ) |
11 |
10
|
com12 |
|- ( ( R Po X /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A R B /\ ( B R C \/ B = C ) ) -> A R C ) ) |
12 |
4 11
|
sylbid |
|- ( ( R Po X /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A R B /\ B ( R u. _I ) C ) -> A R C ) ) |