| Step | Hyp | Ref | Expression | 
						
							| 1 |  | estrcval.c | ⊢ 𝐶  =  ( ExtStrCat ‘ 𝑈 ) | 
						
							| 2 |  | estrcval.u | ⊢ ( 𝜑  →  𝑈  ∈  𝑉 ) | 
						
							| 3 |  | estrcval.h | ⊢ ( 𝜑  →  𝐻  =  ( 𝑥  ∈  𝑈 ,  𝑦  ∈  𝑈  ↦  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) ) ) | 
						
							| 4 |  | estrcval.o | ⊢ ( 𝜑  →   ·   =  ( 𝑣  ∈  ( 𝑈  ×  𝑈 ) ,  𝑧  ∈  𝑈  ↦  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) ) ) | 
						
							| 5 |  | df-estrc | ⊢ ExtStrCat  =  ( 𝑢  ∈  V  ↦  { 〈 ( Base ‘ ndx ) ,  𝑢 〉 ,  〈 ( Hom  ‘ ndx ) ,  ( 𝑥  ∈  𝑢 ,  𝑦  ∈  𝑢  ↦  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) ) 〉 ,  〈 ( comp ‘ ndx ) ,  ( 𝑣  ∈  ( 𝑢  ×  𝑢 ) ,  𝑧  ∈  𝑢  ↦  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) ) 〉 } ) | 
						
							| 6 |  | simpr | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  𝑢  =  𝑈 ) | 
						
							| 7 | 6 | opeq2d | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  〈 ( Base ‘ ndx ) ,  𝑢 〉  =  〈 ( Base ‘ ndx ) ,  𝑈 〉 ) | 
						
							| 8 |  | eqidd | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) )  =  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) ) | 
						
							| 9 | 6 6 8 | mpoeq123dv | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  ( 𝑥  ∈  𝑢 ,  𝑦  ∈  𝑢  ↦  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) )  =  ( 𝑥  ∈  𝑈 ,  𝑦  ∈  𝑈  ↦  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) ) ) | 
						
							| 10 | 3 | adantr | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  𝐻  =  ( 𝑥  ∈  𝑈 ,  𝑦  ∈  𝑈  ↦  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) ) ) | 
						
							| 11 | 9 10 | eqtr4d | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  ( 𝑥  ∈  𝑢 ,  𝑦  ∈  𝑢  ↦  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) )  =  𝐻 ) | 
						
							| 12 | 11 | opeq2d | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  〈 ( Hom  ‘ ndx ) ,  ( 𝑥  ∈  𝑢 ,  𝑦  ∈  𝑢  ↦  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) ) 〉  =  〈 ( Hom  ‘ ndx ) ,  𝐻 〉 ) | 
						
							| 13 | 6 | sqxpeqd | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  ( 𝑢  ×  𝑢 )  =  ( 𝑈  ×  𝑈 ) ) | 
						
							| 14 |  | eqidd | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) )  =  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) ) | 
						
							| 15 | 13 6 14 | mpoeq123dv | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  ( 𝑣  ∈  ( 𝑢  ×  𝑢 ) ,  𝑧  ∈  𝑢  ↦  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) )  =  ( 𝑣  ∈  ( 𝑈  ×  𝑈 ) ,  𝑧  ∈  𝑈  ↦  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) ) ) | 
						
							| 16 | 4 | adantr | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →   ·   =  ( 𝑣  ∈  ( 𝑈  ×  𝑈 ) ,  𝑧  ∈  𝑈  ↦  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) ) ) | 
						
							| 17 | 15 16 | eqtr4d | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  ( 𝑣  ∈  ( 𝑢  ×  𝑢 ) ,  𝑧  ∈  𝑢  ↦  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) )  =   ·  ) | 
						
							| 18 | 17 | opeq2d | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  〈 ( comp ‘ ndx ) ,  ( 𝑣  ∈  ( 𝑢  ×  𝑢 ) ,  𝑧  ∈  𝑢  ↦  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) ) 〉  =  〈 ( comp ‘ ndx ) ,   ·  〉 ) | 
						
							| 19 | 7 12 18 | tpeq123d | ⊢ ( ( 𝜑  ∧  𝑢  =  𝑈 )  →  { 〈 ( Base ‘ ndx ) ,  𝑢 〉 ,  〈 ( Hom  ‘ ndx ) ,  ( 𝑥  ∈  𝑢 ,  𝑦  ∈  𝑢  ↦  ( ( Base ‘ 𝑦 )  ↑m  ( Base ‘ 𝑥 ) ) ) 〉 ,  〈 ( comp ‘ ndx ) ,  ( 𝑣  ∈  ( 𝑢  ×  𝑢 ) ,  𝑧  ∈  𝑢  ↦  ( 𝑔  ∈  ( ( Base ‘ 𝑧 )  ↑m  ( Base ‘ ( 2nd  ‘ 𝑣 ) ) ) ,  𝑓  ∈  ( ( Base ‘ ( 2nd  ‘ 𝑣 ) )  ↑m  ( Base ‘ ( 1st  ‘ 𝑣 ) ) )  ↦  ( 𝑔  ∘  𝑓 ) ) ) 〉 }  =  { 〈 ( Base ‘ ndx ) ,  𝑈 〉 ,  〈 ( Hom  ‘ ndx ) ,  𝐻 〉 ,  〈 ( comp ‘ ndx ) ,   ·  〉 } ) | 
						
							| 20 | 2 | elexd | ⊢ ( 𝜑  →  𝑈  ∈  V ) | 
						
							| 21 |  | tpex | ⊢ { 〈 ( Base ‘ ndx ) ,  𝑈 〉 ,  〈 ( Hom  ‘ ndx ) ,  𝐻 〉 ,  〈 ( comp ‘ ndx ) ,   ·  〉 }  ∈  V | 
						
							| 22 | 21 | a1i | ⊢ ( 𝜑  →  { 〈 ( Base ‘ ndx ) ,  𝑈 〉 ,  〈 ( Hom  ‘ ndx ) ,  𝐻 〉 ,  〈 ( comp ‘ ndx ) ,   ·  〉 }  ∈  V ) | 
						
							| 23 | 5 19 20 22 | fvmptd2 | ⊢ ( 𝜑  →  ( ExtStrCat ‘ 𝑈 )  =  { 〈 ( Base ‘ ndx ) ,  𝑈 〉 ,  〈 ( Hom  ‘ ndx ) ,  𝐻 〉 ,  〈 ( comp ‘ ndx ) ,   ·  〉 } ) | 
						
							| 24 | 1 23 | eqtrid | ⊢ ( 𝜑  →  𝐶  =  { 〈 ( Base ‘ ndx ) ,  𝑈 〉 ,  〈 ( Hom  ‘ ndx ) ,  𝐻 〉 ,  〈 ( comp ‘ ndx ) ,   ·  〉 } ) |