| Step | Hyp | Ref | Expression | 
						
							| 1 |  | tngbas.t | ⊢ 𝑇  =  ( 𝐺  toNrmGrp  𝑁 ) | 
						
							| 2 |  | tngtset.2 | ⊢ 𝐷  =  ( dist ‘ 𝑇 ) | 
						
							| 3 |  | tngtset.3 | ⊢ 𝐽  =  ( MetOpen ‘ 𝐷 ) | 
						
							| 4 |  | ovex | ⊢ ( 𝐺  sSet  〈 ( dist ‘ ndx ) ,  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) 〉 )  ∈  V | 
						
							| 5 |  | fvex | ⊢ ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) )  ∈  V | 
						
							| 6 |  | tsetid | ⊢ TopSet  =  Slot  ( TopSet ‘ ndx ) | 
						
							| 7 | 6 | setsid | ⊢ ( ( ( 𝐺  sSet  〈 ( dist ‘ ndx ) ,  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) 〉 )  ∈  V  ∧  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) )  ∈  V )  →  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) )  =  ( TopSet ‘ ( ( 𝐺  sSet  〈 ( dist ‘ ndx ) ,  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) 〉 )  sSet  〈 ( TopSet ‘ ndx ) ,  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) 〉 ) ) ) | 
						
							| 8 | 4 5 7 | mp2an | ⊢ ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) )  =  ( TopSet ‘ ( ( 𝐺  sSet  〈 ( dist ‘ ndx ) ,  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) 〉 )  sSet  〈 ( TopSet ‘ ndx ) ,  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) 〉 ) ) | 
						
							| 9 |  | eqid | ⊢ ( -g ‘ 𝐺 )  =  ( -g ‘ 𝐺 ) | 
						
							| 10 | 1 9 | tngds | ⊢ ( 𝑁  ∈  𝑊  →  ( 𝑁  ∘  ( -g ‘ 𝐺 ) )  =  ( dist ‘ 𝑇 ) ) | 
						
							| 11 | 2 10 | eqtr4id | ⊢ ( 𝑁  ∈  𝑊  →  𝐷  =  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) | 
						
							| 12 | 11 | adantl | ⊢ ( ( 𝐺  ∈  𝑉  ∧  𝑁  ∈  𝑊 )  →  𝐷  =  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) | 
						
							| 13 | 12 | fveq2d | ⊢ ( ( 𝐺  ∈  𝑉  ∧  𝑁  ∈  𝑊 )  →  ( MetOpen ‘ 𝐷 )  =  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) ) | 
						
							| 14 | 3 13 | eqtrid | ⊢ ( ( 𝐺  ∈  𝑉  ∧  𝑁  ∈  𝑊 )  →  𝐽  =  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) ) | 
						
							| 15 |  | eqid | ⊢ ( 𝑁  ∘  ( -g ‘ 𝐺 ) )  =  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) | 
						
							| 16 |  | eqid | ⊢ ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) )  =  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) | 
						
							| 17 | 1 9 15 16 | tngval | ⊢ ( ( 𝐺  ∈  𝑉  ∧  𝑁  ∈  𝑊 )  →  𝑇  =  ( ( 𝐺  sSet  〈 ( dist ‘ ndx ) ,  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) 〉 )  sSet  〈 ( TopSet ‘ ndx ) ,  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) 〉 ) ) | 
						
							| 18 | 17 | fveq2d | ⊢ ( ( 𝐺  ∈  𝑉  ∧  𝑁  ∈  𝑊 )  →  ( TopSet ‘ 𝑇 )  =  ( TopSet ‘ ( ( 𝐺  sSet  〈 ( dist ‘ ndx ) ,  ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) 〉 )  sSet  〈 ( TopSet ‘ ndx ) ,  ( MetOpen ‘ ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ) 〉 ) ) ) | 
						
							| 19 | 8 14 18 | 3eqtr4a | ⊢ ( ( 𝐺  ∈  𝑉  ∧  𝑁  ∈  𝑊 )  →  𝐽  =  ( TopSet ‘ 𝑇 ) ) |