| Step | Hyp | Ref | Expression | 
						
							| 1 |  | arwlid.h | ⊢ 𝐻  =  ( Homa ‘ 𝐶 ) | 
						
							| 2 |  | arwlid.o | ⊢  ·   =  ( compa ‘ 𝐶 ) | 
						
							| 3 |  | arwlid.a | ⊢  1   =  ( Ida ‘ 𝐶 ) | 
						
							| 4 |  | arwlid.f | ⊢ ( 𝜑  →  𝐹  ∈  ( 𝑋 𝐻 𝑌 ) ) | 
						
							| 5 |  | eqid | ⊢ ( Base ‘ 𝐶 )  =  ( Base ‘ 𝐶 ) | 
						
							| 6 | 1 | homarcl | ⊢ ( 𝐹  ∈  ( 𝑋 𝐻 𝑌 )  →  𝐶  ∈  Cat ) | 
						
							| 7 | 4 6 | syl | ⊢ ( 𝜑  →  𝐶  ∈  Cat ) | 
						
							| 8 |  | eqid | ⊢ ( Id ‘ 𝐶 )  =  ( Id ‘ 𝐶 ) | 
						
							| 9 | 1 5 | homarcl2 | ⊢ ( 𝐹  ∈  ( 𝑋 𝐻 𝑌 )  →  ( 𝑋  ∈  ( Base ‘ 𝐶 )  ∧  𝑌  ∈  ( Base ‘ 𝐶 ) ) ) | 
						
							| 10 | 4 9 | syl | ⊢ ( 𝜑  →  ( 𝑋  ∈  ( Base ‘ 𝐶 )  ∧  𝑌  ∈  ( Base ‘ 𝐶 ) ) ) | 
						
							| 11 | 10 | simpld | ⊢ ( 𝜑  →  𝑋  ∈  ( Base ‘ 𝐶 ) ) | 
						
							| 12 | 3 5 7 8 11 | ida2 | ⊢ ( 𝜑  →  ( 2nd  ‘ (  1  ‘ 𝑋 ) )  =  ( ( Id ‘ 𝐶 ) ‘ 𝑋 ) ) | 
						
							| 13 | 12 | oveq2d | ⊢ ( 𝜑  →  ( ( 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 | ⊢ ( 𝜑  →  𝑌  ∈  ( Base ‘ 𝐶 ) ) | 
						
							| 17 | 1 14 | homahom | ⊢ ( 𝐹  ∈  ( 𝑋 𝐻 𝑌 )  →  ( 2nd  ‘ 𝐹 )  ∈  ( 𝑋 ( Hom  ‘ 𝐶 ) 𝑌 ) ) | 
						
							| 18 | 4 17 | syl | ⊢ ( 𝜑  →  ( 2nd  ‘ 𝐹 )  ∈  ( 𝑋 ( Hom  ‘ 𝐶 ) 𝑌 ) ) | 
						
							| 19 | 5 14 8 7 11 15 16 18 | catrid | ⊢ ( 𝜑  →  ( ( 2nd  ‘ 𝐹 ) ( 〈 𝑋 ,  𝑋 〉 ( comp ‘ 𝐶 ) 𝑌 ) ( ( Id ‘ 𝐶 ) ‘ 𝑋 ) )  =  ( 2nd  ‘ 𝐹 ) ) | 
						
							| 20 | 13 19 | eqtrd | ⊢ ( 𝜑  →  ( ( 2nd  ‘ 𝐹 ) ( 〈 𝑋 ,  𝑋 〉 ( comp ‘ 𝐶 ) 𝑌 ) ( 2nd  ‘ (  1  ‘ 𝑋 ) ) )  =  ( 2nd  ‘ 𝐹 ) ) | 
						
							| 21 | 20 | oteq3d | ⊢ ( 𝜑  →  〈 𝑋 ,  𝑌 ,  ( ( 2nd  ‘ 𝐹 ) ( 〈 𝑋 ,  𝑋 〉 ( comp ‘ 𝐶 ) 𝑌 ) ( 2nd  ‘ (  1  ‘ 𝑋 ) ) ) 〉  =  〈 𝑋 ,  𝑌 ,  ( 2nd  ‘ 𝐹 ) 〉 ) | 
						
							| 22 | 3 5 7 11 1 | idahom | ⊢ ( 𝜑  →  (  1  ‘ 𝑋 )  ∈  ( 𝑋 𝐻 𝑋 ) ) | 
						
							| 23 | 2 1 22 4 15 | coaval | ⊢ ( 𝜑  →  ( 𝐹  ·  (  1  ‘ 𝑋 ) )  =  〈 𝑋 ,  𝑌 ,  ( ( 2nd  ‘ 𝐹 ) ( 〈 𝑋 ,  𝑋 〉 ( comp ‘ 𝐶 ) 𝑌 ) ( 2nd  ‘ (  1  ‘ 𝑋 ) ) ) 〉 ) | 
						
							| 24 | 1 | homadmcd | ⊢ ( 𝐹  ∈  ( 𝑋 𝐻 𝑌 )  →  𝐹  =  〈 𝑋 ,  𝑌 ,  ( 2nd  ‘ 𝐹 ) 〉 ) | 
						
							| 25 | 4 24 | syl | ⊢ ( 𝜑  →  𝐹  =  〈 𝑋 ,  𝑌 ,  ( 2nd  ‘ 𝐹 ) 〉 ) | 
						
							| 26 | 21 23 25 | 3eqtr4d | ⊢ ( 𝜑  →  ( 𝐹  ·  (  1  ‘ 𝑋 ) )  =  𝐹 ) |