| Step | Hyp | Ref | Expression | 
						
							| 1 |  | arwlid.h |  |-  H = ( HomA ` C ) | 
						
							| 2 |  | arwlid.o |  |-  .x. = ( compA ` C ) | 
						
							| 3 |  | arwlid.a |  |-  .1. = ( IdA ` C ) | 
						
							| 4 |  | arwlid.f |  |-  ( ph -> F e. ( X H Y ) ) | 
						
							| 5 |  | eqid |  |-  ( Base ` C ) = ( Base ` C ) | 
						
							| 6 | 1 | homarcl |  |-  ( F e. ( X H Y ) -> C e. Cat ) | 
						
							| 7 | 4 6 | syl |  |-  ( ph -> C e. Cat ) | 
						
							| 8 |  | eqid |  |-  ( Id ` C ) = ( Id ` C ) | 
						
							| 9 | 1 5 | homarcl2 |  |-  ( F e. ( X H Y ) -> ( X e. ( Base ` C ) /\ Y e. ( Base ` C ) ) ) | 
						
							| 10 | 4 9 | syl |  |-  ( ph -> ( X e. ( Base ` C ) /\ Y e. ( Base ` C ) ) ) | 
						
							| 11 | 10 | simpld |  |-  ( ph -> X e. ( Base ` C ) ) | 
						
							| 12 | 3 5 7 8 11 | ida2 |  |-  ( ph -> ( 2nd ` ( .1. ` X ) ) = ( ( Id ` C ) ` X ) ) | 
						
							| 13 | 12 | oveq2d |  |-  ( ph -> ( ( 2nd ` F ) ( <. X , X >. ( comp ` C ) Y ) ( 2nd ` ( .1. ` X ) ) ) = ( ( 2nd ` F ) ( <. X , X >. ( comp ` C ) Y ) ( ( Id ` C ) ` X ) ) ) | 
						
							| 14 |  | eqid |  |-  ( Hom ` C ) = ( Hom ` C ) | 
						
							| 15 |  | eqid |  |-  ( comp ` C ) = ( comp ` C ) | 
						
							| 16 | 10 | simprd |  |-  ( ph -> Y e. ( Base ` C ) ) | 
						
							| 17 | 1 14 | homahom |  |-  ( F e. ( X H Y ) -> ( 2nd ` F ) e. ( X ( Hom ` C ) Y ) ) | 
						
							| 18 | 4 17 | syl |  |-  ( ph -> ( 2nd ` F ) e. ( X ( Hom ` C ) Y ) ) | 
						
							| 19 | 5 14 8 7 11 15 16 18 | catrid |  |-  ( ph -> ( ( 2nd ` F ) ( <. X , X >. ( comp ` C ) Y ) ( ( Id ` C ) ` X ) ) = ( 2nd ` F ) ) | 
						
							| 20 | 13 19 | eqtrd |  |-  ( ph -> ( ( 2nd ` F ) ( <. X , X >. ( comp ` C ) Y ) ( 2nd ` ( .1. ` X ) ) ) = ( 2nd ` F ) ) | 
						
							| 21 | 20 | oteq3d |  |-  ( ph -> <. X , Y , ( ( 2nd ` F ) ( <. X , X >. ( comp ` C ) Y ) ( 2nd ` ( .1. ` X ) ) ) >. = <. X , Y , ( 2nd ` F ) >. ) | 
						
							| 22 | 3 5 7 11 1 | idahom |  |-  ( ph -> ( .1. ` X ) e. ( X H X ) ) | 
						
							| 23 | 2 1 22 4 15 | coaval |  |-  ( ph -> ( F .x. ( .1. ` X ) ) = <. X , Y , ( ( 2nd ` F ) ( <. X , X >. ( comp ` C ) Y ) ( 2nd ` ( .1. ` X ) ) ) >. ) | 
						
							| 24 | 1 | homadmcd |  |-  ( F e. ( X H Y ) -> F = <. X , Y , ( 2nd ` F ) >. ) | 
						
							| 25 | 4 24 | syl |  |-  ( ph -> F = <. X , Y , ( 2nd ` F ) >. ) | 
						
							| 26 | 21 23 25 | 3eqtr4d |  |-  ( ph -> ( F .x. ( .1. ` X ) ) = F ) |