| 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 ) ) |