| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							comfffval.o | 
							 |-  O = ( comf ` C )  | 
						
						
							| 2 | 
							
								
							 | 
							comfffval.b | 
							 |-  B = ( Base ` C )  | 
						
						
							| 3 | 
							
								
							 | 
							comfffval.h | 
							 |-  H = ( Hom ` C )  | 
						
						
							| 4 | 
							
								
							 | 
							comfffval.x | 
							 |-  .x. = ( comp ` C )  | 
						
						
							| 5 | 
							
								
							 | 
							comffval.x | 
							 |-  ( ph -> X e. B )  | 
						
						
							| 6 | 
							
								
							 | 
							comffval.y | 
							 |-  ( ph -> Y e. B )  | 
						
						
							| 7 | 
							
								
							 | 
							comffval.z | 
							 |-  ( ph -> Z e. B )  | 
						
						
							| 8 | 
							
								
							 | 
							comfval.f | 
							 |-  ( ph -> F e. ( X H Y ) )  | 
						
						
							| 9 | 
							
								
							 | 
							comfval.g | 
							 |-  ( ph -> G e. ( Y H Z ) )  | 
						
						
							| 10 | 
							
								1 2 3 4 5 6 7
							 | 
							comffval | 
							 |-  ( ph -> ( <. X , Y >. O Z ) = ( g e. ( Y H Z ) , f e. ( X H Y ) |-> ( g ( <. X , Y >. .x. Z ) f ) ) )  | 
						
						
							| 11 | 
							
								
							 | 
							oveq12 | 
							 |-  ( ( g = G /\ f = F ) -> ( g ( <. X , Y >. .x. Z ) f ) = ( G ( <. X , Y >. .x. Z ) F ) )  | 
						
						
							| 12 | 
							
								11
							 | 
							adantl | 
							 |-  ( ( ph /\ ( g = G /\ f = F ) ) -> ( g ( <. X , Y >. .x. Z ) f ) = ( G ( <. X , Y >. .x. Z ) F ) )  | 
						
						
							| 13 | 
							
								
							 | 
							ovexd | 
							 |-  ( ph -> ( G ( <. X , Y >. .x. Z ) F ) e. _V )  | 
						
						
							| 14 | 
							
								10 12 9 8 13
							 | 
							ovmpod | 
							 |-  ( ph -> ( G ( <. X , Y >. O Z ) F ) = ( G ( <. X , Y >. .x. Z ) F ) )  |