| Step | Hyp | Ref | Expression | 
						
							| 1 |  | caovord.1 |  |-  A e. _V | 
						
							| 2 |  | caovord.2 |  |-  B e. _V | 
						
							| 3 |  | caovord.3 |  |-  ( z e. S -> ( x R y <-> ( z F x ) R ( z F y ) ) ) | 
						
							| 4 |  | oveq1 |  |-  ( z = C -> ( z F A ) = ( C F A ) ) | 
						
							| 5 |  | oveq1 |  |-  ( z = C -> ( z F B ) = ( C F B ) ) | 
						
							| 6 | 4 5 | breq12d |  |-  ( z = C -> ( ( z F A ) R ( z F B ) <-> ( C F A ) R ( C F B ) ) ) | 
						
							| 7 | 6 | bibi2d |  |-  ( z = C -> ( ( A R B <-> ( z F A ) R ( z F B ) ) <-> ( A R B <-> ( C F A ) R ( C F B ) ) ) ) | 
						
							| 8 |  | breq1 |  |-  ( x = A -> ( x R y <-> A R y ) ) | 
						
							| 9 |  | oveq2 |  |-  ( x = A -> ( z F x ) = ( z F A ) ) | 
						
							| 10 | 9 | breq1d |  |-  ( x = A -> ( ( z F x ) R ( z F y ) <-> ( z F A ) R ( z F y ) ) ) | 
						
							| 11 | 8 10 | bibi12d |  |-  ( x = A -> ( ( x R y <-> ( z F x ) R ( z F y ) ) <-> ( A R y <-> ( z F A ) R ( z F y ) ) ) ) | 
						
							| 12 |  | breq2 |  |-  ( y = B -> ( A R y <-> A R B ) ) | 
						
							| 13 |  | oveq2 |  |-  ( y = B -> ( z F y ) = ( z F B ) ) | 
						
							| 14 | 13 | breq2d |  |-  ( y = B -> ( ( z F A ) R ( z F y ) <-> ( z F A ) R ( z F B ) ) ) | 
						
							| 15 | 12 14 | bibi12d |  |-  ( y = B -> ( ( A R y <-> ( z F A ) R ( z F y ) ) <-> ( A R B <-> ( z F A ) R ( z F B ) ) ) ) | 
						
							| 16 | 11 15 | sylan9bb |  |-  ( ( x = A /\ y = B ) -> ( ( x R y <-> ( z F x ) R ( z F y ) ) <-> ( A R B <-> ( z F A ) R ( z F B ) ) ) ) | 
						
							| 17 | 16 | imbi2d |  |-  ( ( x = A /\ y = B ) -> ( ( z e. S -> ( x R y <-> ( z F x ) R ( z F y ) ) ) <-> ( z e. S -> ( A R B <-> ( z F A ) R ( z F B ) ) ) ) ) | 
						
							| 18 | 1 2 17 3 | vtocl2 |  |-  ( z e. S -> ( A R B <-> ( z F A ) R ( z F B ) ) ) | 
						
							| 19 | 7 18 | vtoclga |  |-  ( C e. S -> ( A R B <-> ( C F A ) R ( C F B ) ) ) |