| Step | Hyp | Ref | Expression | 
						
							| 1 |  | tngnm.t | ⊢ 𝑇  =  ( 𝐺  toNrmGrp  𝑁 ) | 
						
							| 2 |  | tngnm.x | ⊢ 𝑋  =  ( Base ‘ 𝐺 ) | 
						
							| 3 |  | tngnm.a | ⊢ 𝐴  ∈  V | 
						
							| 4 |  | simpr | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  𝑁 : 𝑋 ⟶ 𝐴 ) | 
						
							| 5 | 4 | feqmptd | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  𝑁  =  ( 𝑥  ∈  𝑋  ↦  ( 𝑁 ‘ 𝑥 ) ) ) | 
						
							| 6 |  | eqid | ⊢ ( -g ‘ 𝐺 )  =  ( -g ‘ 𝐺 ) | 
						
							| 7 | 2 6 | grpsubf | ⊢ ( 𝐺  ∈  Grp  →  ( -g ‘ 𝐺 ) : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 ) | 
						
							| 8 | 7 | ad2antrr | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  ( -g ‘ 𝐺 ) : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 ) | 
						
							| 9 |  | simpr | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  𝑥  ∈  𝑋 ) | 
						
							| 10 |  | eqid | ⊢ ( 0g ‘ 𝐺 )  =  ( 0g ‘ 𝐺 ) | 
						
							| 11 | 2 10 | grpidcl | ⊢ ( 𝐺  ∈  Grp  →  ( 0g ‘ 𝐺 )  ∈  𝑋 ) | 
						
							| 12 | 11 | ad2antrr | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  ( 0g ‘ 𝐺 )  ∈  𝑋 ) | 
						
							| 13 | 9 12 | opelxpd | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉  ∈  ( 𝑋  ×  𝑋 ) ) | 
						
							| 14 |  | fvco3 | ⊢ ( ( ( -g ‘ 𝐺 ) : ( 𝑋  ×  𝑋 ) ⟶ 𝑋  ∧  〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉  ∈  ( 𝑋  ×  𝑋 ) )  →  ( ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ‘ 〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉 )  =  ( 𝑁 ‘ ( ( -g ‘ 𝐺 ) ‘ 〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉 ) ) ) | 
						
							| 15 | 8 13 14 | syl2anc | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  ( ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ‘ 〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉 )  =  ( 𝑁 ‘ ( ( -g ‘ 𝐺 ) ‘ 〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉 ) ) ) | 
						
							| 16 |  | df-ov | ⊢ ( 𝑥 ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ( 0g ‘ 𝐺 ) )  =  ( ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ‘ 〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉 ) | 
						
							| 17 |  | df-ov | ⊢ ( 𝑥 ( -g ‘ 𝐺 ) ( 0g ‘ 𝐺 ) )  =  ( ( -g ‘ 𝐺 ) ‘ 〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉 ) | 
						
							| 18 | 17 | fveq2i | ⊢ ( 𝑁 ‘ ( 𝑥 ( -g ‘ 𝐺 ) ( 0g ‘ 𝐺 ) ) )  =  ( 𝑁 ‘ ( ( -g ‘ 𝐺 ) ‘ 〈 𝑥 ,  ( 0g ‘ 𝐺 ) 〉 ) ) | 
						
							| 19 | 15 16 18 | 3eqtr4g | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  ( 𝑥 ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ( 0g ‘ 𝐺 ) )  =  ( 𝑁 ‘ ( 𝑥 ( -g ‘ 𝐺 ) ( 0g ‘ 𝐺 ) ) ) ) | 
						
							| 20 | 2 10 6 | grpsubid1 | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑥  ∈  𝑋 )  →  ( 𝑥 ( -g ‘ 𝐺 ) ( 0g ‘ 𝐺 ) )  =  𝑥 ) | 
						
							| 21 | 20 | adantlr | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  ( 𝑥 ( -g ‘ 𝐺 ) ( 0g ‘ 𝐺 ) )  =  𝑥 ) | 
						
							| 22 | 21 | fveq2d | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  ( 𝑁 ‘ ( 𝑥 ( -g ‘ 𝐺 ) ( 0g ‘ 𝐺 ) ) )  =  ( 𝑁 ‘ 𝑥 ) ) | 
						
							| 23 | 19 22 | eqtr2d | ⊢ ( ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  ∧  𝑥  ∈  𝑋 )  →  ( 𝑁 ‘ 𝑥 )  =  ( 𝑥 ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ( 0g ‘ 𝐺 ) ) ) | 
						
							| 24 | 23 | mpteq2dva | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  ( 𝑥  ∈  𝑋  ↦  ( 𝑁 ‘ 𝑥 ) )  =  ( 𝑥  ∈  𝑋  ↦  ( 𝑥 ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ( 0g ‘ 𝐺 ) ) ) ) | 
						
							| 25 | 2 | fvexi | ⊢ 𝑋  ∈  V | 
						
							| 26 |  | fex2 | ⊢ ( ( 𝑁 : 𝑋 ⟶ 𝐴  ∧  𝑋  ∈  V  ∧  𝐴  ∈  V )  →  𝑁  ∈  V ) | 
						
							| 27 | 25 3 26 | mp3an23 | ⊢ ( 𝑁 : 𝑋 ⟶ 𝐴  →  𝑁  ∈  V ) | 
						
							| 28 | 27 | adantl | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  𝑁  ∈  V ) | 
						
							| 29 | 1 2 | tngbas | ⊢ ( 𝑁  ∈  V  →  𝑋  =  ( Base ‘ 𝑇 ) ) | 
						
							| 30 | 28 29 | syl | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  𝑋  =  ( Base ‘ 𝑇 ) ) | 
						
							| 31 | 1 6 | tngds | ⊢ ( 𝑁  ∈  V  →  ( 𝑁  ∘  ( -g ‘ 𝐺 ) )  =  ( dist ‘ 𝑇 ) ) | 
						
							| 32 | 28 31 | syl | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  ( 𝑁  ∘  ( -g ‘ 𝐺 ) )  =  ( dist ‘ 𝑇 ) ) | 
						
							| 33 |  | eqidd | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  𝑥  =  𝑥 ) | 
						
							| 34 | 1 10 | tng0 | ⊢ ( 𝑁  ∈  V  →  ( 0g ‘ 𝐺 )  =  ( 0g ‘ 𝑇 ) ) | 
						
							| 35 | 28 34 | syl | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  ( 0g ‘ 𝐺 )  =  ( 0g ‘ 𝑇 ) ) | 
						
							| 36 | 32 33 35 | oveq123d | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  ( 𝑥 ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ( 0g ‘ 𝐺 ) )  =  ( 𝑥 ( dist ‘ 𝑇 ) ( 0g ‘ 𝑇 ) ) ) | 
						
							| 37 | 30 36 | mpteq12dv | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  ( 𝑥  ∈  𝑋  ↦  ( 𝑥 ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ( 0g ‘ 𝐺 ) ) )  =  ( 𝑥  ∈  ( Base ‘ 𝑇 )  ↦  ( 𝑥 ( dist ‘ 𝑇 ) ( 0g ‘ 𝑇 ) ) ) ) | 
						
							| 38 |  | eqid | ⊢ ( norm ‘ 𝑇 )  =  ( norm ‘ 𝑇 ) | 
						
							| 39 |  | eqid | ⊢ ( Base ‘ 𝑇 )  =  ( Base ‘ 𝑇 ) | 
						
							| 40 |  | eqid | ⊢ ( 0g ‘ 𝑇 )  =  ( 0g ‘ 𝑇 ) | 
						
							| 41 |  | eqid | ⊢ ( dist ‘ 𝑇 )  =  ( dist ‘ 𝑇 ) | 
						
							| 42 | 38 39 40 41 | nmfval | ⊢ ( norm ‘ 𝑇 )  =  ( 𝑥  ∈  ( Base ‘ 𝑇 )  ↦  ( 𝑥 ( dist ‘ 𝑇 ) ( 0g ‘ 𝑇 ) ) ) | 
						
							| 43 | 37 42 | eqtr4di | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  ( 𝑥  ∈  𝑋  ↦  ( 𝑥 ( 𝑁  ∘  ( -g ‘ 𝐺 ) ) ( 0g ‘ 𝐺 ) ) )  =  ( norm ‘ 𝑇 ) ) | 
						
							| 44 | 5 24 43 | 3eqtrd | ⊢ ( ( 𝐺  ∈  Grp  ∧  𝑁 : 𝑋 ⟶ 𝐴 )  →  𝑁  =  ( norm ‘ 𝑇 ) ) |