| Step | Hyp | Ref | Expression | 
						
							| 1 |  | breq1 |  |-  ( a = A -> ( a Range b <-> A Range b ) ) | 
						
							| 2 |  | rneq |  |-  ( a = A -> ran a = ran A ) | 
						
							| 3 | 2 | eqeq2d |  |-  ( a = A -> ( b = ran a <-> b = ran A ) ) | 
						
							| 4 | 1 3 | bibi12d |  |-  ( a = A -> ( ( a Range b <-> b = ran a ) <-> ( A Range b <-> b = ran A ) ) ) | 
						
							| 5 |  | breq2 |  |-  ( b = B -> ( A Range b <-> A Range B ) ) | 
						
							| 6 |  | eqeq1 |  |-  ( b = B -> ( b = ran A <-> B = ran A ) ) | 
						
							| 7 | 5 6 | bibi12d |  |-  ( b = B -> ( ( A Range b <-> b = ran A ) <-> ( A Range B <-> B = ran A ) ) ) | 
						
							| 8 |  | vex |  |-  a e. _V | 
						
							| 9 |  | vex |  |-  b e. _V | 
						
							| 10 | 8 9 | brrange |  |-  ( a Range b <-> b = ran a ) | 
						
							| 11 | 4 7 10 | vtocl2g |  |-  ( ( A e. V /\ B e. W ) -> ( A Range B <-> B = ran A ) ) |