| Step | Hyp | Ref | Expression | 
						
							| 1 |  | oppcval.b | ⊢ 𝐵  =  ( Base ‘ 𝐶 ) | 
						
							| 2 |  | oppcval.h | ⊢ 𝐻  =  ( Hom  ‘ 𝐶 ) | 
						
							| 3 |  | oppcval.x | ⊢  ·   =  ( comp ‘ 𝐶 ) | 
						
							| 4 |  | oppcval.o | ⊢ 𝑂  =  ( oppCat ‘ 𝐶 ) | 
						
							| 5 |  | elex | ⊢ ( 𝐶  ∈  𝑉  →  𝐶  ∈  V ) | 
						
							| 6 |  | id | ⊢ ( 𝑐  =  𝐶  →  𝑐  =  𝐶 ) | 
						
							| 7 |  | fveq2 | ⊢ ( 𝑐  =  𝐶  →  ( Hom  ‘ 𝑐 )  =  ( Hom  ‘ 𝐶 ) ) | 
						
							| 8 | 7 2 | eqtr4di | ⊢ ( 𝑐  =  𝐶  →  ( Hom  ‘ 𝑐 )  =  𝐻 ) | 
						
							| 9 | 8 | tposeqd | ⊢ ( 𝑐  =  𝐶  →  tpos  ( Hom  ‘ 𝑐 )  =  tpos  𝐻 ) | 
						
							| 10 | 9 | opeq2d | ⊢ ( 𝑐  =  𝐶  →  〈 ( Hom  ‘ ndx ) ,  tpos  ( Hom  ‘ 𝑐 ) 〉  =  〈 ( Hom  ‘ ndx ) ,  tpos  𝐻 〉 ) | 
						
							| 11 | 6 10 | oveq12d | ⊢ ( 𝑐  =  𝐶  →  ( 𝑐  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  ( Hom  ‘ 𝑐 ) 〉 )  =  ( 𝐶  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  𝐻 〉 ) ) | 
						
							| 12 |  | fveq2 | ⊢ ( 𝑐  =  𝐶  →  ( Base ‘ 𝑐 )  =  ( Base ‘ 𝐶 ) ) | 
						
							| 13 | 12 1 | eqtr4di | ⊢ ( 𝑐  =  𝐶  →  ( Base ‘ 𝑐 )  =  𝐵 ) | 
						
							| 14 | 13 | sqxpeqd | ⊢ ( 𝑐  =  𝐶  →  ( ( Base ‘ 𝑐 )  ×  ( Base ‘ 𝑐 ) )  =  ( 𝐵  ×  𝐵 ) ) | 
						
							| 15 |  | fveq2 | ⊢ ( 𝑐  =  𝐶  →  ( comp ‘ 𝑐 )  =  ( comp ‘ 𝐶 ) ) | 
						
							| 16 | 15 3 | eqtr4di | ⊢ ( 𝑐  =  𝐶  →  ( comp ‘ 𝑐 )  =   ·  ) | 
						
							| 17 | 16 | oveqd | ⊢ ( 𝑐  =  𝐶  →  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉 ( comp ‘ 𝑐 ) ( 1st  ‘ 𝑢 ) )  =  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) | 
						
							| 18 | 17 | tposeqd | ⊢ ( 𝑐  =  𝐶  →  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉 ( comp ‘ 𝑐 ) ( 1st  ‘ 𝑢 ) )  =  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) | 
						
							| 19 | 14 13 18 | mpoeq123dv | ⊢ ( 𝑐  =  𝐶  →  ( 𝑢  ∈  ( ( Base ‘ 𝑐 )  ×  ( Base ‘ 𝑐 ) ) ,  𝑧  ∈  ( Base ‘ 𝑐 )  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉 ( comp ‘ 𝑐 ) ( 1st  ‘ 𝑢 ) ) )  =  ( 𝑢  ∈  ( 𝐵  ×  𝐵 ) ,  𝑧  ∈  𝐵  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) ) | 
						
							| 20 | 19 | opeq2d | ⊢ ( 𝑐  =  𝐶  →  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( ( Base ‘ 𝑐 )  ×  ( Base ‘ 𝑐 ) ) ,  𝑧  ∈  ( Base ‘ 𝑐 )  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉 ( comp ‘ 𝑐 ) ( 1st  ‘ 𝑢 ) ) ) 〉  =  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( 𝐵  ×  𝐵 ) ,  𝑧  ∈  𝐵  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) 〉 ) | 
						
							| 21 | 11 20 | oveq12d | ⊢ ( 𝑐  =  𝐶  →  ( ( 𝑐  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  ( Hom  ‘ 𝑐 ) 〉 )  sSet  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( ( Base ‘ 𝑐 )  ×  ( Base ‘ 𝑐 ) ) ,  𝑧  ∈  ( Base ‘ 𝑐 )  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉 ( comp ‘ 𝑐 ) ( 1st  ‘ 𝑢 ) ) ) 〉 )  =  ( ( 𝐶  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  𝐻 〉 )  sSet  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( 𝐵  ×  𝐵 ) ,  𝑧  ∈  𝐵  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) 〉 ) ) | 
						
							| 22 |  | df-oppc | ⊢ oppCat  =  ( 𝑐  ∈  V  ↦  ( ( 𝑐  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  ( Hom  ‘ 𝑐 ) 〉 )  sSet  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( ( Base ‘ 𝑐 )  ×  ( Base ‘ 𝑐 ) ) ,  𝑧  ∈  ( Base ‘ 𝑐 )  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉 ( comp ‘ 𝑐 ) ( 1st  ‘ 𝑢 ) ) ) 〉 ) ) | 
						
							| 23 |  | ovex | ⊢ ( ( 𝐶  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  𝐻 〉 )  sSet  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( 𝐵  ×  𝐵 ) ,  𝑧  ∈  𝐵  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) 〉 )  ∈  V | 
						
							| 24 | 21 22 23 | fvmpt | ⊢ ( 𝐶  ∈  V  →  ( oppCat ‘ 𝐶 )  =  ( ( 𝐶  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  𝐻 〉 )  sSet  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( 𝐵  ×  𝐵 ) ,  𝑧  ∈  𝐵  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) 〉 ) ) | 
						
							| 25 | 5 24 | syl | ⊢ ( 𝐶  ∈  𝑉  →  ( oppCat ‘ 𝐶 )  =  ( ( 𝐶  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  𝐻 〉 )  sSet  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( 𝐵  ×  𝐵 ) ,  𝑧  ∈  𝐵  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) 〉 ) ) | 
						
							| 26 | 4 25 | eqtrid | ⊢ ( 𝐶  ∈  𝑉  →  𝑂  =  ( ( 𝐶  sSet  〈 ( Hom  ‘ ndx ) ,  tpos  𝐻 〉 )  sSet  〈 ( comp ‘ ndx ) ,  ( 𝑢  ∈  ( 𝐵  ×  𝐵 ) ,  𝑧  ∈  𝐵  ↦  tpos  ( 〈 𝑧 ,  ( 2nd  ‘ 𝑢 ) 〉  ·  ( 1st  ‘ 𝑢 ) ) ) 〉 ) ) |