| Step | Hyp | Ref | Expression | 
						
							| 1 |  | oppcbas.1 | ⊢ 𝑂  =  ( oppCat ‘ 𝐶 ) | 
						
							| 2 |  | eqid | ⊢ ( Base ‘ 𝐶 )  =  ( Base ‘ 𝐶 ) | 
						
							| 3 | 1 2 | oppcbas | ⊢ ( Base ‘ 𝐶 )  =  ( Base ‘ 𝑂 ) | 
						
							| 4 | 3 | a1i | ⊢ ( 𝐶  ∈  Cat  →  ( Base ‘ 𝐶 )  =  ( Base ‘ 𝑂 ) ) | 
						
							| 5 |  | eqidd | ⊢ ( 𝐶  ∈  Cat  →  ( Hom  ‘ 𝑂 )  =  ( Hom  ‘ 𝑂 ) ) | 
						
							| 6 |  | eqidd | ⊢ ( 𝐶  ∈  Cat  →  ( comp ‘ 𝑂 )  =  ( comp ‘ 𝑂 ) ) | 
						
							| 7 | 1 | fvexi | ⊢ 𝑂  ∈  V | 
						
							| 8 | 7 | a1i | ⊢ ( 𝐶  ∈  Cat  →  𝑂  ∈  V ) | 
						
							| 9 |  | biid | ⊢ ( ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) )  ↔  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) ) | 
						
							| 10 |  | eqid | ⊢ ( Hom  ‘ 𝐶 )  =  ( Hom  ‘ 𝐶 ) | 
						
							| 11 |  | eqid | ⊢ ( Id ‘ 𝐶 )  =  ( Id ‘ 𝐶 ) | 
						
							| 12 |  | simpl | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  →  𝐶  ∈  Cat ) | 
						
							| 13 |  | simpr | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  →  𝑦  ∈  ( Base ‘ 𝐶 ) ) | 
						
							| 14 | 2 10 11 12 13 | catidcl | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  →  ( ( Id ‘ 𝐶 ) ‘ 𝑦 )  ∈  ( 𝑦 ( Hom  ‘ 𝐶 ) 𝑦 ) ) | 
						
							| 15 | 10 1 | oppchom | ⊢ ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑦 )  =  ( 𝑦 ( Hom  ‘ 𝐶 ) 𝑦 ) | 
						
							| 16 | 14 15 | eleqtrrdi | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  →  ( ( Id ‘ 𝐶 ) ‘ 𝑦 )  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑦 ) ) | 
						
							| 17 |  | eqid | ⊢ ( comp ‘ 𝐶 )  =  ( comp ‘ 𝐶 ) | 
						
							| 18 |  | simpr1l | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝑥  ∈  ( Base ‘ 𝐶 ) ) | 
						
							| 19 |  | simpr1r | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝑦  ∈  ( Base ‘ 𝐶 ) ) | 
						
							| 20 | 2 17 1 18 19 19 | oppcco | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑦 ) 𝑓 )  =  ( 𝑓 ( 〈 𝑦 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ) ) | 
						
							| 21 |  | simpl | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝐶  ∈  Cat ) | 
						
							| 22 |  | simpr31 | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 ) ) | 
						
							| 23 | 10 1 | oppchom | ⊢ ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  =  ( 𝑦 ( Hom  ‘ 𝐶 ) 𝑥 ) | 
						
							| 24 | 22 23 | eleqtrdi | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝑓  ∈  ( 𝑦 ( Hom  ‘ 𝐶 ) 𝑥 ) ) | 
						
							| 25 | 2 10 11 21 19 17 18 24 | catrid | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( 𝑓 ( 〈 𝑦 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) )  =  𝑓 ) | 
						
							| 26 | 20 25 | eqtrd | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑦 ) 𝑓 )  =  𝑓 ) | 
						
							| 27 |  | simpr2l | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝑧  ∈  ( Base ‘ 𝐶 ) ) | 
						
							| 28 | 2 17 1 19 19 27 | oppcco | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( 𝑔 ( 〈 𝑦 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑧 ) ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) )  =  ( ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑦 ) 𝑔 ) ) | 
						
							| 29 |  | simpr32 | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 ) ) | 
						
							| 30 | 10 1 | oppchom | ⊢ ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  =  ( 𝑧 ( Hom  ‘ 𝐶 ) 𝑦 ) | 
						
							| 31 | 29 30 | eleqtrdi | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝑔  ∈  ( 𝑧 ( Hom  ‘ 𝐶 ) 𝑦 ) ) | 
						
							| 32 | 2 10 11 21 27 17 19 31 | catlid | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑦 ) 𝑔 )  =  𝑔 ) | 
						
							| 33 | 28 32 | eqtrd | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( 𝑔 ( 〈 𝑦 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑧 ) ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) )  =  𝑔 ) | 
						
							| 34 | 2 17 1 18 19 27 | oppcco | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑧 ) 𝑓 )  =  ( 𝑓 ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) 𝑔 ) ) | 
						
							| 35 | 2 10 17 21 27 19 18 31 24 | catcocl | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( 𝑓 ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) 𝑔 )  ∈  ( 𝑧 ( Hom  ‘ 𝐶 ) 𝑥 ) ) | 
						
							| 36 | 34 35 | eqeltrd | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑧 ) 𝑓 )  ∈  ( 𝑧 ( Hom  ‘ 𝐶 ) 𝑥 ) ) | 
						
							| 37 | 10 1 | oppchom | ⊢ ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑧 )  =  ( 𝑧 ( Hom  ‘ 𝐶 ) 𝑥 ) | 
						
							| 38 | 36 37 | eleqtrrdi | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑧 ) ) | 
						
							| 39 |  | simpr2r | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  𝑤  ∈  ( Base ‘ 𝐶 ) ) | 
						
							| 40 |  | simpr33 | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) | 
						
							| 41 | 10 1 | oppchom | ⊢ ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 )  =  ( 𝑤 ( Hom  ‘ 𝐶 ) 𝑧 ) | 
						
							| 42 | 40 41 | eleqtrdi | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ℎ  ∈  ( 𝑤 ( Hom  ‘ 𝐶 ) 𝑧 ) ) | 
						
							| 43 | 2 10 17 21 39 27 19 42 31 18 24 | catass | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ( 𝑓 ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) 𝑔 ) ( 〈 𝑤 ,  𝑧 〉 ( comp ‘ 𝐶 ) 𝑥 ) ℎ )  =  ( 𝑓 ( 〈 𝑤 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) ( 𝑔 ( 〈 𝑤 ,  𝑧 〉 ( comp ‘ 𝐶 ) 𝑦 ) ℎ ) ) ) | 
						
							| 44 | 2 17 1 18 27 39 | oppcco | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ℎ ( 〈 𝑥 ,  𝑧 〉 ( comp ‘ 𝑂 ) 𝑤 ) ( 𝑓 ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) 𝑔 ) )  =  ( ( 𝑓 ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) 𝑔 ) ( 〈 𝑤 ,  𝑧 〉 ( comp ‘ 𝐶 ) 𝑥 ) ℎ ) ) | 
						
							| 45 | 2 17 1 18 19 39 | oppcco | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ( 𝑔 ( 〈 𝑤 ,  𝑧 〉 ( comp ‘ 𝐶 ) 𝑦 ) ℎ ) ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑤 ) 𝑓 )  =  ( 𝑓 ( 〈 𝑤 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) ( 𝑔 ( 〈 𝑤 ,  𝑧 〉 ( comp ‘ 𝐶 ) 𝑦 ) ℎ ) ) ) | 
						
							| 46 | 43 44 45 | 3eqtr4rd | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ( 𝑔 ( 〈 𝑤 ,  𝑧 〉 ( comp ‘ 𝐶 ) 𝑦 ) ℎ ) ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑤 ) 𝑓 )  =  ( ℎ ( 〈 𝑥 ,  𝑧 〉 ( comp ‘ 𝑂 ) 𝑤 ) ( 𝑓 ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) 𝑔 ) ) ) | 
						
							| 47 | 2 17 1 19 27 39 | oppcco | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ℎ ( 〈 𝑦 ,  𝑧 〉 ( comp ‘ 𝑂 ) 𝑤 ) 𝑔 )  =  ( 𝑔 ( 〈 𝑤 ,  𝑧 〉 ( comp ‘ 𝐶 ) 𝑦 ) ℎ ) ) | 
						
							| 48 | 47 | oveq1d | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ( ℎ ( 〈 𝑦 ,  𝑧 〉 ( comp ‘ 𝑂 ) 𝑤 ) 𝑔 ) ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑤 ) 𝑓 )  =  ( ( 𝑔 ( 〈 𝑤 ,  𝑧 〉 ( comp ‘ 𝐶 ) 𝑦 ) ℎ ) ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑤 ) 𝑓 ) ) | 
						
							| 49 | 34 | oveq2d | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ℎ ( 〈 𝑥 ,  𝑧 〉 ( comp ‘ 𝑂 ) 𝑤 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑧 ) 𝑓 ) )  =  ( ℎ ( 〈 𝑥 ,  𝑧 〉 ( comp ‘ 𝑂 ) 𝑤 ) ( 𝑓 ( 〈 𝑧 ,  𝑦 〉 ( comp ‘ 𝐶 ) 𝑥 ) 𝑔 ) ) ) | 
						
							| 50 | 46 48 49 | 3eqtr4d | ⊢ ( ( 𝐶  ∈  Cat  ∧  ( ( 𝑥  ∈  ( Base ‘ 𝐶 )  ∧  𝑦  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑧  ∈  ( Base ‘ 𝐶 )  ∧  𝑤  ∈  ( Base ‘ 𝐶 ) )  ∧  ( 𝑓  ∈  ( 𝑥 ( Hom  ‘ 𝑂 ) 𝑦 )  ∧  𝑔  ∈  ( 𝑦 ( Hom  ‘ 𝑂 ) 𝑧 )  ∧  ℎ  ∈  ( 𝑧 ( Hom  ‘ 𝑂 ) 𝑤 ) ) ) )  →  ( ( ℎ ( 〈 𝑦 ,  𝑧 〉 ( comp ‘ 𝑂 ) 𝑤 ) 𝑔 ) ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑤 ) 𝑓 )  =  ( ℎ ( 〈 𝑥 ,  𝑧 〉 ( comp ‘ 𝑂 ) 𝑤 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑂 ) 𝑧 ) 𝑓 ) ) ) | 
						
							| 51 | 4 5 6 8 9 16 26 33 38 50 | iscatd2 | ⊢ ( 𝐶  ∈  Cat  →  ( 𝑂  ∈  Cat  ∧  ( Id ‘ 𝑂 )  =  ( 𝑦  ∈  ( Base ‘ 𝐶 )  ↦  ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ) ) ) | 
						
							| 52 | 2 11 | cidfn | ⊢ ( 𝐶  ∈  Cat  →  ( Id ‘ 𝐶 )  Fn  ( Base ‘ 𝐶 ) ) | 
						
							| 53 |  | dffn5 | ⊢ ( ( Id ‘ 𝐶 )  Fn  ( Base ‘ 𝐶 )  ↔  ( Id ‘ 𝐶 )  =  ( 𝑦  ∈  ( Base ‘ 𝐶 )  ↦  ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ) ) | 
						
							| 54 | 52 53 | sylib | ⊢ ( 𝐶  ∈  Cat  →  ( Id ‘ 𝐶 )  =  ( 𝑦  ∈  ( Base ‘ 𝐶 )  ↦  ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ) ) | 
						
							| 55 | 54 | eqeq2d | ⊢ ( 𝐶  ∈  Cat  →  ( ( Id ‘ 𝑂 )  =  ( Id ‘ 𝐶 )  ↔  ( Id ‘ 𝑂 )  =  ( 𝑦  ∈  ( Base ‘ 𝐶 )  ↦  ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ) ) ) | 
						
							| 56 | 55 | anbi2d | ⊢ ( 𝐶  ∈  Cat  →  ( ( 𝑂  ∈  Cat  ∧  ( Id ‘ 𝑂 )  =  ( Id ‘ 𝐶 ) )  ↔  ( 𝑂  ∈  Cat  ∧  ( Id ‘ 𝑂 )  =  ( 𝑦  ∈  ( Base ‘ 𝐶 )  ↦  ( ( Id ‘ 𝐶 ) ‘ 𝑦 ) ) ) ) ) | 
						
							| 57 | 51 56 | mpbird | ⊢ ( 𝐶  ∈  Cat  →  ( 𝑂  ∈  Cat  ∧  ( Id ‘ 𝑂 )  =  ( Id ‘ 𝐶 ) ) ) |