| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eqid | ⊢ ( ℤRHom ‘ 𝑅 )  =  ( ℤRHom ‘ 𝑅 ) | 
						
							| 2 | 1 | zrhrhm | ⊢ ( 𝑅  ∈  Ring  →  ( ℤRHom ‘ 𝑅 )  ∈  ( ℤring  RingHom  𝑅 ) ) | 
						
							| 3 |  | eqid | ⊢ ( mulGrp ‘ ℤring )  =  ( mulGrp ‘ ℤring ) | 
						
							| 4 |  | eqid | ⊢ ( mulGrp ‘ 𝑅 )  =  ( mulGrp ‘ 𝑅 ) | 
						
							| 5 | 3 4 | rhmmhm | ⊢ ( ( ℤRHom ‘ 𝑅 )  ∈  ( ℤring  RingHom  𝑅 )  →  ( ℤRHom ‘ 𝑅 )  ∈  ( ( mulGrp ‘ ℤring )  MndHom  ( mulGrp ‘ 𝑅 ) ) ) | 
						
							| 6 | 2 5 | syl | ⊢ ( 𝑅  ∈  Ring  →  ( ℤRHom ‘ 𝑅 )  ∈  ( ( mulGrp ‘ ℤring )  MndHom  ( mulGrp ‘ 𝑅 ) ) ) | 
						
							| 7 |  | eqid | ⊢ ( SymGrp ‘ 𝐴 )  =  ( SymGrp ‘ 𝐴 ) | 
						
							| 8 |  | eqid | ⊢ ( pmSgn ‘ 𝐴 )  =  ( pmSgn ‘ 𝐴 ) | 
						
							| 9 |  | eqid | ⊢ ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } )  =  ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } ) | 
						
							| 10 | 7 8 9 | psgnghm2 | ⊢ ( 𝐴  ∈  Fin  →  ( pmSgn ‘ 𝐴 )  ∈  ( ( SymGrp ‘ 𝐴 )  GrpHom  ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } ) ) ) | 
						
							| 11 |  | ghmmhm | ⊢ ( ( pmSgn ‘ 𝐴 )  ∈  ( ( SymGrp ‘ 𝐴 )  GrpHom  ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } ) )  →  ( pmSgn ‘ 𝐴 )  ∈  ( ( SymGrp ‘ 𝐴 )  MndHom  ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } ) ) ) | 
						
							| 12 | 10 11 | syl | ⊢ ( 𝐴  ∈  Fin  →  ( pmSgn ‘ 𝐴 )  ∈  ( ( SymGrp ‘ 𝐴 )  MndHom  ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } ) ) ) | 
						
							| 13 |  | eqid | ⊢ ( ( mulGrp ‘ ℂfld )  ↾s  ( ℂ  ∖  { 0 } ) )  =  ( ( mulGrp ‘ ℂfld )  ↾s  ( ℂ  ∖  { 0 } ) ) | 
						
							| 14 | 13 | cnmsgnsubg | ⊢ { 1 ,  - 1 }  ∈  ( SubGrp ‘ ( ( mulGrp ‘ ℂfld )  ↾s  ( ℂ  ∖  { 0 } ) ) ) | 
						
							| 15 |  | subgsubm | ⊢ ( { 1 ,  - 1 }  ∈  ( SubGrp ‘ ( ( mulGrp ‘ ℂfld )  ↾s  ( ℂ  ∖  { 0 } ) ) )  →  { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( ( mulGrp ‘ ℂfld )  ↾s  ( ℂ  ∖  { 0 } ) ) ) ) | 
						
							| 16 | 14 15 | ax-mp | ⊢ { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( ( mulGrp ‘ ℂfld )  ↾s  ( ℂ  ∖  { 0 } ) ) ) | 
						
							| 17 |  | cnring | ⊢ ℂfld  ∈  Ring | 
						
							| 18 |  | cnfldbas | ⊢ ℂ  =  ( Base ‘ ℂfld ) | 
						
							| 19 |  | cnfld0 | ⊢ 0  =  ( 0g ‘ ℂfld ) | 
						
							| 20 |  | cndrng | ⊢ ℂfld  ∈  DivRing | 
						
							| 21 | 18 19 20 | drngui | ⊢ ( ℂ  ∖  { 0 } )  =  ( Unit ‘ ℂfld ) | 
						
							| 22 |  | eqid | ⊢ ( mulGrp ‘ ℂfld )  =  ( mulGrp ‘ ℂfld ) | 
						
							| 23 | 21 22 | unitsubm | ⊢ ( ℂfld  ∈  Ring  →  ( ℂ  ∖  { 0 } )  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) ) ) | 
						
							| 24 | 13 | subsubm | ⊢ ( ( ℂ  ∖  { 0 } )  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) )  →  ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( ( mulGrp ‘ ℂfld )  ↾s  ( ℂ  ∖  { 0 } ) ) )  ↔  ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) )  ∧  { 1 ,  - 1 }  ⊆  ( ℂ  ∖  { 0 } ) ) ) ) | 
						
							| 25 | 17 23 24 | mp2b | ⊢ ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( ( mulGrp ‘ ℂfld )  ↾s  ( ℂ  ∖  { 0 } ) ) )  ↔  ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) )  ∧  { 1 ,  - 1 }  ⊆  ( ℂ  ∖  { 0 } ) ) ) | 
						
							| 26 | 16 25 | mpbi | ⊢ ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) )  ∧  { 1 ,  - 1 }  ⊆  ( ℂ  ∖  { 0 } ) ) | 
						
							| 27 | 26 | simpli | ⊢ { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) ) | 
						
							| 28 |  | 1z | ⊢ 1  ∈  ℤ | 
						
							| 29 |  | neg1z | ⊢ - 1  ∈  ℤ | 
						
							| 30 |  | prssi | ⊢ ( ( 1  ∈  ℤ  ∧  - 1  ∈  ℤ )  →  { 1 ,  - 1 }  ⊆  ℤ ) | 
						
							| 31 | 28 29 30 | mp2an | ⊢ { 1 ,  - 1 }  ⊆  ℤ | 
						
							| 32 |  | zsubrg | ⊢ ℤ  ∈  ( SubRing ‘ ℂfld ) | 
						
							| 33 | 22 | subrgsubm | ⊢ ( ℤ  ∈  ( SubRing ‘ ℂfld )  →  ℤ  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) ) ) | 
						
							| 34 |  | zringmpg | ⊢ ( ( mulGrp ‘ ℂfld )  ↾s  ℤ )  =  ( mulGrp ‘ ℤring ) | 
						
							| 35 | 34 | eqcomi | ⊢ ( mulGrp ‘ ℤring )  =  ( ( mulGrp ‘ ℂfld )  ↾s  ℤ ) | 
						
							| 36 | 35 | subsubm | ⊢ ( ℤ  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) )  →  ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℤring ) )  ↔  ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) )  ∧  { 1 ,  - 1 }  ⊆  ℤ ) ) ) | 
						
							| 37 | 32 33 36 | mp2b | ⊢ ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℤring ) )  ↔  ( { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℂfld ) )  ∧  { 1 ,  - 1 }  ⊆  ℤ ) ) | 
						
							| 38 | 27 31 37 | mpbir2an | ⊢ { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℤring ) ) | 
						
							| 39 |  | zex | ⊢ ℤ  ∈  V | 
						
							| 40 |  | ressabs | ⊢ ( ( ℤ  ∈  V  ∧  { 1 ,  - 1 }  ⊆  ℤ )  →  ( ( ( mulGrp ‘ ℂfld )  ↾s  ℤ )  ↾s  { 1 ,  - 1 } )  =  ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } ) ) | 
						
							| 41 | 39 31 40 | mp2an | ⊢ ( ( ( mulGrp ‘ ℂfld )  ↾s  ℤ )  ↾s  { 1 ,  - 1 } )  =  ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } ) | 
						
							| 42 | 34 | oveq1i | ⊢ ( ( ( mulGrp ‘ ℂfld )  ↾s  ℤ )  ↾s  { 1 ,  - 1 } )  =  ( ( mulGrp ‘ ℤring )  ↾s  { 1 ,  - 1 } ) | 
						
							| 43 | 41 42 | eqtr3i | ⊢ ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } )  =  ( ( mulGrp ‘ ℤring )  ↾s  { 1 ,  - 1 } ) | 
						
							| 44 | 43 | resmhm2 | ⊢ ( ( ( pmSgn ‘ 𝐴 )  ∈  ( ( SymGrp ‘ 𝐴 )  MndHom  ( ( mulGrp ‘ ℂfld )  ↾s  { 1 ,  - 1 } ) )  ∧  { 1 ,  - 1 }  ∈  ( SubMnd ‘ ( mulGrp ‘ ℤring ) ) )  →  ( pmSgn ‘ 𝐴 )  ∈  ( ( SymGrp ‘ 𝐴 )  MndHom  ( mulGrp ‘ ℤring ) ) ) | 
						
							| 45 | 12 38 44 | sylancl | ⊢ ( 𝐴  ∈  Fin  →  ( pmSgn ‘ 𝐴 )  ∈  ( ( SymGrp ‘ 𝐴 )  MndHom  ( mulGrp ‘ ℤring ) ) ) | 
						
							| 46 |  | mhmco | ⊢ ( ( ( ℤRHom ‘ 𝑅 )  ∈  ( ( mulGrp ‘ ℤring )  MndHom  ( mulGrp ‘ 𝑅 ) )  ∧  ( pmSgn ‘ 𝐴 )  ∈  ( ( SymGrp ‘ 𝐴 )  MndHom  ( mulGrp ‘ ℤring ) ) )  →  ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝐴 ) )  ∈  ( ( SymGrp ‘ 𝐴 )  MndHom  ( mulGrp ‘ 𝑅 ) ) ) | 
						
							| 47 | 6 45 46 | syl2an | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝐴  ∈  Fin )  →  ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝐴 ) )  ∈  ( ( SymGrp ‘ 𝐴 )  MndHom  ( mulGrp ‘ 𝑅 ) ) ) |