| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							comfeqval.b | 
							⊢ 𝐵  =  ( Base ‘ 𝐶 )  | 
						
						
							| 2 | 
							
								
							 | 
							comfeqval.h | 
							⊢ 𝐻  =  ( Hom  ‘ 𝐶 )  | 
						
						
							| 3 | 
							
								
							 | 
							comfeqval.1 | 
							⊢  ·   =  ( comp ‘ 𝐶 )  | 
						
						
							| 4 | 
							
								
							 | 
							comfeqval.2 | 
							⊢  ∙   =  ( comp ‘ 𝐷 )  | 
						
						
							| 5 | 
							
								
							 | 
							comfeqval.3 | 
							⊢ ( 𝜑  →  ( Homf  ‘ 𝐶 )  =  ( Homf  ‘ 𝐷 ) )  | 
						
						
							| 6 | 
							
								
							 | 
							comfeqval.4 | 
							⊢ ( 𝜑  →  ( compf ‘ 𝐶 )  =  ( compf ‘ 𝐷 ) )  | 
						
						
							| 7 | 
							
								
							 | 
							comfeqval.x | 
							⊢ ( 𝜑  →  𝑋  ∈  𝐵 )  | 
						
						
							| 8 | 
							
								
							 | 
							comfeqval.y | 
							⊢ ( 𝜑  →  𝑌  ∈  𝐵 )  | 
						
						
							| 9 | 
							
								
							 | 
							comfeqval.z | 
							⊢ ( 𝜑  →  𝑍  ∈  𝐵 )  | 
						
						
							| 10 | 
							
								
							 | 
							comfeqval.f | 
							⊢ ( 𝜑  →  𝐹  ∈  ( 𝑋 𝐻 𝑌 ) )  | 
						
						
							| 11 | 
							
								
							 | 
							comfeqval.g | 
							⊢ ( 𝜑  →  𝐺  ∈  ( 𝑌 𝐻 𝑍 ) )  | 
						
						
							| 12 | 
							
								6
							 | 
							oveqd | 
							⊢ ( 𝜑  →  ( 〈 𝑋 ,  𝑌 〉 ( compf ‘ 𝐶 ) 𝑍 )  =  ( 〈 𝑋 ,  𝑌 〉 ( compf ‘ 𝐷 ) 𝑍 ) )  | 
						
						
							| 13 | 
							
								12
							 | 
							oveqd | 
							⊢ ( 𝜑  →  ( 𝐺 ( 〈 𝑋 ,  𝑌 〉 ( compf ‘ 𝐶 ) 𝑍 ) 𝐹 )  =  ( 𝐺 ( 〈 𝑋 ,  𝑌 〉 ( compf ‘ 𝐷 ) 𝑍 ) 𝐹 ) )  | 
						
						
							| 14 | 
							
								
							 | 
							eqid | 
							⊢ ( compf ‘ 𝐶 )  =  ( compf ‘ 𝐶 )  | 
						
						
							| 15 | 
							
								14 1 2 3 7 8 9 10 11
							 | 
							comfval | 
							⊢ ( 𝜑  →  ( 𝐺 ( 〈 𝑋 ,  𝑌 〉 ( compf ‘ 𝐶 ) 𝑍 ) 𝐹 )  =  ( 𝐺 ( 〈 𝑋 ,  𝑌 〉  ·  𝑍 ) 𝐹 ) )  | 
						
						
							| 16 | 
							
								
							 | 
							eqid | 
							⊢ ( compf ‘ 𝐷 )  =  ( compf ‘ 𝐷 )  | 
						
						
							| 17 | 
							
								
							 | 
							eqid | 
							⊢ ( Base ‘ 𝐷 )  =  ( Base ‘ 𝐷 )  | 
						
						
							| 18 | 
							
								
							 | 
							eqid | 
							⊢ ( Hom  ‘ 𝐷 )  =  ( Hom  ‘ 𝐷 )  | 
						
						
							| 19 | 
							
								5
							 | 
							homfeqbas | 
							⊢ ( 𝜑  →  ( Base ‘ 𝐶 )  =  ( Base ‘ 𝐷 ) )  | 
						
						
							| 20 | 
							
								1 19
							 | 
							eqtrid | 
							⊢ ( 𝜑  →  𝐵  =  ( Base ‘ 𝐷 ) )  | 
						
						
							| 21 | 
							
								7 20
							 | 
							eleqtrd | 
							⊢ ( 𝜑  →  𝑋  ∈  ( Base ‘ 𝐷 ) )  | 
						
						
							| 22 | 
							
								8 20
							 | 
							eleqtrd | 
							⊢ ( 𝜑  →  𝑌  ∈  ( Base ‘ 𝐷 ) )  | 
						
						
							| 23 | 
							
								9 20
							 | 
							eleqtrd | 
							⊢ ( 𝜑  →  𝑍  ∈  ( Base ‘ 𝐷 ) )  | 
						
						
							| 24 | 
							
								1 2 18 5 7 8
							 | 
							homfeqval | 
							⊢ ( 𝜑  →  ( 𝑋 𝐻 𝑌 )  =  ( 𝑋 ( Hom  ‘ 𝐷 ) 𝑌 ) )  | 
						
						
							| 25 | 
							
								10 24
							 | 
							eleqtrd | 
							⊢ ( 𝜑  →  𝐹  ∈  ( 𝑋 ( Hom  ‘ 𝐷 ) 𝑌 ) )  | 
						
						
							| 26 | 
							
								1 2 18 5 8 9
							 | 
							homfeqval | 
							⊢ ( 𝜑  →  ( 𝑌 𝐻 𝑍 )  =  ( 𝑌 ( Hom  ‘ 𝐷 ) 𝑍 ) )  | 
						
						
							| 27 | 
							
								11 26
							 | 
							eleqtrd | 
							⊢ ( 𝜑  →  𝐺  ∈  ( 𝑌 ( Hom  ‘ 𝐷 ) 𝑍 ) )  | 
						
						
							| 28 | 
							
								16 17 18 4 21 22 23 25 27
							 | 
							comfval | 
							⊢ ( 𝜑  →  ( 𝐺 ( 〈 𝑋 ,  𝑌 〉 ( compf ‘ 𝐷 ) 𝑍 ) 𝐹 )  =  ( 𝐺 ( 〈 𝑋 ,  𝑌 〉  ∙  𝑍 ) 𝐹 ) )  | 
						
						
							| 29 | 
							
								13 15 28
							 | 
							3eqtr3d | 
							⊢ ( 𝜑  →  ( 𝐺 ( 〈 𝑋 ,  𝑌 〉  ·  𝑍 ) 𝐹 )  =  ( 𝐺 ( 〈 𝑋 ,  𝑌 〉  ∙  𝑍 ) 𝐹 ) )  |