| Step | Hyp | Ref | Expression | 
						
							| 1 |  | fucass.q |  |-  Q = ( C FuncCat D ) | 
						
							| 2 |  | fucass.n |  |-  N = ( C Nat D ) | 
						
							| 3 |  | fucass.x |  |-  .xb = ( comp ` Q ) | 
						
							| 4 |  | fucass.r |  |-  ( ph -> R e. ( F N G ) ) | 
						
							| 5 |  | fucass.s |  |-  ( ph -> S e. ( G N H ) ) | 
						
							| 6 |  | fucass.t |  |-  ( ph -> T e. ( H N K ) ) | 
						
							| 7 |  | eqid |  |-  ( Base ` D ) = ( Base ` D ) | 
						
							| 8 |  | eqid |  |-  ( Hom ` D ) = ( Hom ` D ) | 
						
							| 9 |  | eqid |  |-  ( comp ` D ) = ( comp ` D ) | 
						
							| 10 | 2 | natrcl |  |-  ( R e. ( F N G ) -> ( F e. ( C Func D ) /\ G e. ( C Func D ) ) ) | 
						
							| 11 | 4 10 | syl |  |-  ( ph -> ( F e. ( C Func D ) /\ G e. ( C Func D ) ) ) | 
						
							| 12 | 11 | simpld |  |-  ( ph -> F e. ( C Func D ) ) | 
						
							| 13 |  | funcrcl |  |-  ( F e. ( C Func D ) -> ( C e. Cat /\ D e. Cat ) ) | 
						
							| 14 | 12 13 | syl |  |-  ( ph -> ( C e. Cat /\ D e. Cat ) ) | 
						
							| 15 | 14 | simprd |  |-  ( ph -> D e. Cat ) | 
						
							| 16 | 15 | adantr |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> D e. Cat ) | 
						
							| 17 |  | eqid |  |-  ( Base ` C ) = ( Base ` C ) | 
						
							| 18 |  | relfunc |  |-  Rel ( C Func D ) | 
						
							| 19 |  | 1st2ndbr |  |-  ( ( Rel ( C Func D ) /\ F e. ( C Func D ) ) -> ( 1st ` F ) ( C Func D ) ( 2nd ` F ) ) | 
						
							| 20 | 18 12 19 | sylancr |  |-  ( ph -> ( 1st ` F ) ( C Func D ) ( 2nd ` F ) ) | 
						
							| 21 | 17 7 20 | funcf1 |  |-  ( ph -> ( 1st ` F ) : ( Base ` C ) --> ( Base ` D ) ) | 
						
							| 22 | 21 | ffvelcdmda |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( 1st ` F ) ` x ) e. ( Base ` D ) ) | 
						
							| 23 | 11 | simprd |  |-  ( ph -> G e. ( C Func D ) ) | 
						
							| 24 |  | 1st2ndbr |  |-  ( ( Rel ( C Func D ) /\ G e. ( C Func D ) ) -> ( 1st ` G ) ( C Func D ) ( 2nd ` G ) ) | 
						
							| 25 | 18 23 24 | sylancr |  |-  ( ph -> ( 1st ` G ) ( C Func D ) ( 2nd ` G ) ) | 
						
							| 26 | 17 7 25 | funcf1 |  |-  ( ph -> ( 1st ` G ) : ( Base ` C ) --> ( Base ` D ) ) | 
						
							| 27 | 26 | ffvelcdmda |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( 1st ` G ) ` x ) e. ( Base ` D ) ) | 
						
							| 28 | 2 | natrcl |  |-  ( T e. ( H N K ) -> ( H e. ( C Func D ) /\ K e. ( C Func D ) ) ) | 
						
							| 29 | 6 28 | syl |  |-  ( ph -> ( H e. ( C Func D ) /\ K e. ( C Func D ) ) ) | 
						
							| 30 | 29 | simpld |  |-  ( ph -> H e. ( C Func D ) ) | 
						
							| 31 |  | 1st2ndbr |  |-  ( ( Rel ( C Func D ) /\ H e. ( C Func D ) ) -> ( 1st ` H ) ( C Func D ) ( 2nd ` H ) ) | 
						
							| 32 | 18 30 31 | sylancr |  |-  ( ph -> ( 1st ` H ) ( C Func D ) ( 2nd ` H ) ) | 
						
							| 33 | 17 7 32 | funcf1 |  |-  ( ph -> ( 1st ` H ) : ( Base ` C ) --> ( Base ` D ) ) | 
						
							| 34 | 33 | ffvelcdmda |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( 1st ` H ) ` x ) e. ( Base ` D ) ) | 
						
							| 35 | 2 4 | nat1st2nd |  |-  ( ph -> R e. ( <. ( 1st ` F ) , ( 2nd ` F ) >. N <. ( 1st ` G ) , ( 2nd ` G ) >. ) ) | 
						
							| 36 | 35 | adantr |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> R e. ( <. ( 1st ` F ) , ( 2nd ` F ) >. N <. ( 1st ` G ) , ( 2nd ` G ) >. ) ) | 
						
							| 37 |  | simpr |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> x e. ( Base ` C ) ) | 
						
							| 38 | 2 36 17 8 37 | natcl |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( R ` x ) e. ( ( ( 1st ` F ) ` x ) ( Hom ` D ) ( ( 1st ` G ) ` x ) ) ) | 
						
							| 39 | 2 5 | nat1st2nd |  |-  ( ph -> S e. ( <. ( 1st ` G ) , ( 2nd ` G ) >. N <. ( 1st ` H ) , ( 2nd ` H ) >. ) ) | 
						
							| 40 | 39 | adantr |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> S e. ( <. ( 1st ` G ) , ( 2nd ` G ) >. N <. ( 1st ` H ) , ( 2nd ` H ) >. ) ) | 
						
							| 41 | 2 40 17 8 37 | natcl |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( S ` x ) e. ( ( ( 1st ` G ) ` x ) ( Hom ` D ) ( ( 1st ` H ) ` x ) ) ) | 
						
							| 42 | 29 | simprd |  |-  ( ph -> K e. ( C Func D ) ) | 
						
							| 43 |  | 1st2ndbr |  |-  ( ( Rel ( C Func D ) /\ K e. ( C Func D ) ) -> ( 1st ` K ) ( C Func D ) ( 2nd ` K ) ) | 
						
							| 44 | 18 42 43 | sylancr |  |-  ( ph -> ( 1st ` K ) ( C Func D ) ( 2nd ` K ) ) | 
						
							| 45 | 17 7 44 | funcf1 |  |-  ( ph -> ( 1st ` K ) : ( Base ` C ) --> ( Base ` D ) ) | 
						
							| 46 | 45 | ffvelcdmda |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( 1st ` K ) ` x ) e. ( Base ` D ) ) | 
						
							| 47 | 2 6 | nat1st2nd |  |-  ( ph -> T e. ( <. ( 1st ` H ) , ( 2nd ` H ) >. N <. ( 1st ` K ) , ( 2nd ` K ) >. ) ) | 
						
							| 48 | 47 | adantr |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> T e. ( <. ( 1st ` H ) , ( 2nd ` H ) >. N <. ( 1st ` K ) , ( 2nd ` K ) >. ) ) | 
						
							| 49 | 2 48 17 8 37 | natcl |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( T ` x ) e. ( ( ( 1st ` H ) ` x ) ( Hom ` D ) ( ( 1st ` K ) ` x ) ) ) | 
						
							| 50 | 7 8 9 16 22 27 34 38 41 46 49 | catass |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( ( T ` x ) ( <. ( ( 1st ` G ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( S ` x ) ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( R ` x ) ) = ( ( T ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( ( S ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` H ) ` x ) ) ( R ` x ) ) ) ) | 
						
							| 51 | 5 | adantr |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> S e. ( G N H ) ) | 
						
							| 52 | 6 | adantr |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> T e. ( H N K ) ) | 
						
							| 53 | 1 2 17 9 3 51 52 37 | fuccoval |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( T ( <. G , H >. .xb K ) S ) ` x ) = ( ( T ` x ) ( <. ( ( 1st ` G ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( S ` x ) ) ) | 
						
							| 54 | 53 | oveq1d |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( ( T ( <. G , H >. .xb K ) S ) ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( R ` x ) ) = ( ( ( T ` x ) ( <. ( ( 1st ` G ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( S ` x ) ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( R ` x ) ) ) | 
						
							| 55 | 4 | adantr |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> R e. ( F N G ) ) | 
						
							| 56 | 1 2 17 9 3 55 51 37 | fuccoval |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( S ( <. F , G >. .xb H ) R ) ` x ) = ( ( S ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` H ) ` x ) ) ( R ` x ) ) ) | 
						
							| 57 | 56 | oveq2d |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( T ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( ( S ( <. F , G >. .xb H ) R ) ` x ) ) = ( ( T ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( ( S ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` H ) ` x ) ) ( R ` x ) ) ) ) | 
						
							| 58 | 50 54 57 | 3eqtr4d |  |-  ( ( ph /\ x e. ( Base ` C ) ) -> ( ( ( T ( <. G , H >. .xb K ) S ) ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( R ` x ) ) = ( ( T ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( ( S ( <. F , G >. .xb H ) R ) ` x ) ) ) | 
						
							| 59 | 58 | mpteq2dva |  |-  ( ph -> ( x e. ( Base ` C ) |-> ( ( ( T ( <. G , H >. .xb K ) S ) ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( R ` x ) ) ) = ( x e. ( Base ` C ) |-> ( ( T ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( ( S ( <. F , G >. .xb H ) R ) ` x ) ) ) ) | 
						
							| 60 | 1 2 3 5 6 | fuccocl |  |-  ( ph -> ( T ( <. G , H >. .xb K ) S ) e. ( G N K ) ) | 
						
							| 61 | 1 2 17 9 3 4 60 | fucco |  |-  ( ph -> ( ( T ( <. G , H >. .xb K ) S ) ( <. F , G >. .xb K ) R ) = ( x e. ( Base ` C ) |-> ( ( ( T ( <. G , H >. .xb K ) S ) ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` G ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( R ` x ) ) ) ) | 
						
							| 62 | 1 2 3 4 5 | fuccocl |  |-  ( ph -> ( S ( <. F , G >. .xb H ) R ) e. ( F N H ) ) | 
						
							| 63 | 1 2 17 9 3 62 6 | fucco |  |-  ( ph -> ( T ( <. F , H >. .xb K ) ( S ( <. F , G >. .xb H ) R ) ) = ( x e. ( Base ` C ) |-> ( ( T ` x ) ( <. ( ( 1st ` F ) ` x ) , ( ( 1st ` H ) ` x ) >. ( comp ` D ) ( ( 1st ` K ) ` x ) ) ( ( S ( <. F , G >. .xb H ) R ) ` x ) ) ) ) | 
						
							| 64 | 59 61 63 | 3eqtr4d |  |-  ( ph -> ( ( T ( <. G , H >. .xb K ) S ) ( <. F , G >. .xb K ) R ) = ( T ( <. F , H >. .xb K ) ( S ( <. F , G >. .xb H ) R ) ) ) |