| Step | Hyp | Ref | Expression | 
						
							| 1 |  | oppchofcl.o |  |-  O = ( oppCat ` C ) | 
						
							| 2 |  | oppchofcl.m |  |-  M = ( HomF ` O ) | 
						
							| 3 |  | oppchofcl.d |  |-  D = ( SetCat ` U ) | 
						
							| 4 |  | oppchofcl.c |  |-  ( ph -> C e. Cat ) | 
						
							| 5 |  | oppchofcl.u |  |-  ( ph -> U e. V ) | 
						
							| 6 |  | oppchofcl.h |  |-  ( ph -> ran ( Homf ` C ) C_ U ) | 
						
							| 7 |  | eqid |  |-  ( oppCat ` O ) = ( oppCat ` O ) | 
						
							| 8 | 1 | oppccat |  |-  ( C e. Cat -> O e. Cat ) | 
						
							| 9 | 4 8 | syl |  |-  ( ph -> O e. Cat ) | 
						
							| 10 |  | eqid |  |-  ( Homf ` C ) = ( Homf ` C ) | 
						
							| 11 | 1 10 | oppchomf |  |-  tpos ( Homf ` C ) = ( Homf ` O ) | 
						
							| 12 | 11 | rneqi |  |-  ran tpos ( Homf ` C ) = ran ( Homf ` O ) | 
						
							| 13 |  | relxp |  |-  Rel ( ( Base ` C ) X. ( Base ` C ) ) | 
						
							| 14 |  | eqid |  |-  ( Base ` C ) = ( Base ` C ) | 
						
							| 15 | 10 14 | homffn |  |-  ( Homf ` C ) Fn ( ( Base ` C ) X. ( Base ` C ) ) | 
						
							| 16 | 15 | fndmi |  |-  dom ( Homf ` C ) = ( ( Base ` C ) X. ( Base ` C ) ) | 
						
							| 17 | 16 | releqi |  |-  ( Rel dom ( Homf ` C ) <-> Rel ( ( Base ` C ) X. ( Base ` C ) ) ) | 
						
							| 18 | 13 17 | mpbir |  |-  Rel dom ( Homf ` C ) | 
						
							| 19 |  | rntpos |  |-  ( Rel dom ( Homf ` C ) -> ran tpos ( Homf ` C ) = ran ( Homf ` C ) ) | 
						
							| 20 | 18 19 | ax-mp |  |-  ran tpos ( Homf ` C ) = ran ( Homf ` C ) | 
						
							| 21 | 12 20 | eqtr3i |  |-  ran ( Homf ` O ) = ran ( Homf ` C ) | 
						
							| 22 | 21 6 | eqsstrid |  |-  ( ph -> ran ( Homf ` O ) C_ U ) | 
						
							| 23 | 2 7 3 9 5 22 | hofcl |  |-  ( ph -> M e. ( ( ( oppCat ` O ) Xc. O ) Func D ) ) | 
						
							| 24 | 1 | 2oppchomf |  |-  ( Homf ` C ) = ( Homf ` ( oppCat ` O ) ) | 
						
							| 25 | 24 | a1i |  |-  ( ph -> ( Homf ` C ) = ( Homf ` ( oppCat ` O ) ) ) | 
						
							| 26 | 1 | 2oppccomf |  |-  ( comf ` C ) = ( comf ` ( oppCat ` O ) ) | 
						
							| 27 | 26 | a1i |  |-  ( ph -> ( comf ` C ) = ( comf ` ( oppCat ` O ) ) ) | 
						
							| 28 |  | eqidd |  |-  ( ph -> ( Homf ` O ) = ( Homf ` O ) ) | 
						
							| 29 |  | eqidd |  |-  ( ph -> ( comf ` O ) = ( comf ` O ) ) | 
						
							| 30 | 7 | oppccat |  |-  ( O e. Cat -> ( oppCat ` O ) e. Cat ) | 
						
							| 31 | 9 30 | syl |  |-  ( ph -> ( oppCat ` O ) e. Cat ) | 
						
							| 32 | 25 27 28 29 4 31 9 9 | xpcpropd |  |-  ( ph -> ( C Xc. O ) = ( ( oppCat ` O ) Xc. O ) ) | 
						
							| 33 | 32 | oveq1d |  |-  ( ph -> ( ( C Xc. O ) Func D ) = ( ( ( oppCat ` O ) Xc. O ) Func D ) ) | 
						
							| 34 | 23 33 | eleqtrrd |  |-  ( ph -> M e. ( ( C Xc. O ) Func D ) ) |