| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdetfval.d | ⊢ 𝐷  =  ( 𝑁  maDet  𝑅 ) | 
						
							| 2 |  | mdetfval.a | ⊢ 𝐴  =  ( 𝑁  Mat  𝑅 ) | 
						
							| 3 |  | mdetfval.b | ⊢ 𝐵  =  ( Base ‘ 𝐴 ) | 
						
							| 4 |  | mdetfval.p | ⊢ 𝑃  =  ( Base ‘ ( SymGrp ‘ 𝑁 ) ) | 
						
							| 5 |  | mdetfval.y | ⊢ 𝑌  =  ( ℤRHom ‘ 𝑅 ) | 
						
							| 6 |  | mdetfval.s | ⊢ 𝑆  =  ( pmSgn ‘ 𝑁 ) | 
						
							| 7 |  | mdetfval.t | ⊢  ·   =  ( .r ‘ 𝑅 ) | 
						
							| 8 |  | mdetfval.u | ⊢ 𝑈  =  ( mulGrp ‘ 𝑅 ) | 
						
							| 9 |  | oveq12 | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( 𝑛  Mat  𝑟 )  =  ( 𝑁  Mat  𝑅 ) ) | 
						
							| 10 | 9 2 | eqtr4di | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( 𝑛  Mat  𝑟 )  =  𝐴 ) | 
						
							| 11 | 10 | fveq2d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( Base ‘ ( 𝑛  Mat  𝑟 ) )  =  ( Base ‘ 𝐴 ) ) | 
						
							| 12 | 11 3 | eqtr4di | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( Base ‘ ( 𝑛  Mat  𝑟 ) )  =  𝐵 ) | 
						
							| 13 |  | simpr | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  𝑟  =  𝑅 ) | 
						
							| 14 |  | simpl | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  𝑛  =  𝑁 ) | 
						
							| 15 | 14 | fveq2d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( SymGrp ‘ 𝑛 )  =  ( SymGrp ‘ 𝑁 ) ) | 
						
							| 16 | 15 | fveq2d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( Base ‘ ( SymGrp ‘ 𝑛 ) )  =  ( Base ‘ ( SymGrp ‘ 𝑁 ) ) ) | 
						
							| 17 | 16 4 | eqtr4di | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( Base ‘ ( SymGrp ‘ 𝑛 ) )  =  𝑃 ) | 
						
							| 18 |  | fveq2 | ⊢ ( 𝑟  =  𝑅  →  ( .r ‘ 𝑟 )  =  ( .r ‘ 𝑅 ) ) | 
						
							| 19 | 18 | adantl | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( .r ‘ 𝑟 )  =  ( .r ‘ 𝑅 ) ) | 
						
							| 20 | 19 7 | eqtr4di | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( .r ‘ 𝑟 )  =   ·  ) | 
						
							| 21 | 13 | fveq2d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( ℤRHom ‘ 𝑟 )  =  ( ℤRHom ‘ 𝑅 ) ) | 
						
							| 22 | 21 5 | eqtr4di | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( ℤRHom ‘ 𝑟 )  =  𝑌 ) | 
						
							| 23 |  | fveq2 | ⊢ ( 𝑛  =  𝑁  →  ( pmSgn ‘ 𝑛 )  =  ( pmSgn ‘ 𝑁 ) ) | 
						
							| 24 | 23 | adantr | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( pmSgn ‘ 𝑛 )  =  ( pmSgn ‘ 𝑁 ) ) | 
						
							| 25 | 24 6 | eqtr4di | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( pmSgn ‘ 𝑛 )  =  𝑆 ) | 
						
							| 26 | 22 25 | coeq12d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( ( ℤRHom ‘ 𝑟 )  ∘  ( pmSgn ‘ 𝑛 ) )  =  ( 𝑌  ∘  𝑆 ) ) | 
						
							| 27 | 26 | fveq1d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( ( ( ℤRHom ‘ 𝑟 )  ∘  ( pmSgn ‘ 𝑛 ) ) ‘ 𝑝 )  =  ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 ) ) | 
						
							| 28 |  | fveq2 | ⊢ ( 𝑟  =  𝑅  →  ( mulGrp ‘ 𝑟 )  =  ( mulGrp ‘ 𝑅 ) ) | 
						
							| 29 | 28 | adantl | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( mulGrp ‘ 𝑟 )  =  ( mulGrp ‘ 𝑅 ) ) | 
						
							| 30 | 29 8 | eqtr4di | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( mulGrp ‘ 𝑟 )  =  𝑈 ) | 
						
							| 31 | 14 | mpteq1d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( 𝑥  ∈  𝑛  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) )  =  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) | 
						
							| 32 | 30 31 | oveq12d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( ( mulGrp ‘ 𝑟 )  Σg  ( 𝑥  ∈  𝑛  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) )  =  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) | 
						
							| 33 | 20 27 32 | oveq123d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( ( ( ( ℤRHom ‘ 𝑟 )  ∘  ( pmSgn ‘ 𝑛 ) ) ‘ 𝑝 ) ( .r ‘ 𝑟 ) ( ( mulGrp ‘ 𝑟 )  Σg  ( 𝑥  ∈  𝑛  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) )  =  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) | 
						
							| 34 | 17 33 | mpteq12dv | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( 𝑝  ∈  ( Base ‘ ( SymGrp ‘ 𝑛 ) )  ↦  ( ( ( ( ℤRHom ‘ 𝑟 )  ∘  ( pmSgn ‘ 𝑛 ) ) ‘ 𝑝 ) ( .r ‘ 𝑟 ) ( ( mulGrp ‘ 𝑟 )  Σg  ( 𝑥  ∈  𝑛  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) )  =  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) | 
						
							| 35 | 13 34 | oveq12d | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( 𝑟  Σg  ( 𝑝  ∈  ( Base ‘ ( SymGrp ‘ 𝑛 ) )  ↦  ( ( ( ( ℤRHom ‘ 𝑟 )  ∘  ( pmSgn ‘ 𝑛 ) ) ‘ 𝑝 ) ( .r ‘ 𝑟 ) ( ( mulGrp ‘ 𝑟 )  Σg  ( 𝑥  ∈  𝑛  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) )  =  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) | 
						
							| 36 | 12 35 | mpteq12dv | ⊢ ( ( 𝑛  =  𝑁  ∧  𝑟  =  𝑅 )  →  ( 𝑚  ∈  ( Base ‘ ( 𝑛  Mat  𝑟 ) )  ↦  ( 𝑟  Σg  ( 𝑝  ∈  ( Base ‘ ( SymGrp ‘ 𝑛 ) )  ↦  ( ( ( ( ℤRHom ‘ 𝑟 )  ∘  ( pmSgn ‘ 𝑛 ) ) ‘ 𝑝 ) ( .r ‘ 𝑟 ) ( ( mulGrp ‘ 𝑟 )  Σg  ( 𝑥  ∈  𝑛  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) )  =  ( 𝑚  ∈  𝐵  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) ) | 
						
							| 37 |  | df-mdet | ⊢  maDet   =  ( 𝑛  ∈  V ,  𝑟  ∈  V  ↦  ( 𝑚  ∈  ( Base ‘ ( 𝑛  Mat  𝑟 ) )  ↦  ( 𝑟  Σg  ( 𝑝  ∈  ( Base ‘ ( SymGrp ‘ 𝑛 ) )  ↦  ( ( ( ( ℤRHom ‘ 𝑟 )  ∘  ( pmSgn ‘ 𝑛 ) ) ‘ 𝑝 ) ( .r ‘ 𝑟 ) ( ( mulGrp ‘ 𝑟 )  Σg  ( 𝑥  ∈  𝑛  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) ) | 
						
							| 38 | 3 | fvexi | ⊢ 𝐵  ∈  V | 
						
							| 39 | 38 | mptex | ⊢ ( 𝑚  ∈  𝐵  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) )  ∈  V | 
						
							| 40 | 36 37 39 | ovmpoa | ⊢ ( ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  ( 𝑁  maDet  𝑅 )  =  ( 𝑚  ∈  𝐵  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) ) | 
						
							| 41 | 37 | reldmmpo | ⊢ Rel  dom   maDet | 
						
							| 42 | 41 | ovprc | ⊢ ( ¬  ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  ( 𝑁  maDet  𝑅 )  =  ∅ ) | 
						
							| 43 |  | mpt0 | ⊢ ( 𝑚  ∈  ∅  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) )  =  ∅ | 
						
							| 44 | 42 43 | eqtr4di | ⊢ ( ¬  ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  ( 𝑁  maDet  𝑅 )  =  ( 𝑚  ∈  ∅  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) ) | 
						
							| 45 |  | df-mat | ⊢  Mat   =  ( 𝑦  ∈  Fin ,  𝑧  ∈  V  ↦  ( ( 𝑧  freeLMod  ( 𝑦  ×  𝑦 ) )  sSet  〈 ( .r ‘ ndx ) ,  ( 𝑧  maMul  〈 𝑦 ,  𝑦 ,  𝑦 〉 ) 〉 ) ) | 
						
							| 46 | 45 | reldmmpo | ⊢ Rel  dom   Mat | 
						
							| 47 | 46 | ovprc | ⊢ ( ¬  ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  ( 𝑁  Mat  𝑅 )  =  ∅ ) | 
						
							| 48 | 2 47 | eqtrid | ⊢ ( ¬  ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  𝐴  =  ∅ ) | 
						
							| 49 | 48 | fveq2d | ⊢ ( ¬  ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  ( Base ‘ 𝐴 )  =  ( Base ‘ ∅ ) ) | 
						
							| 50 |  | base0 | ⊢ ∅  =  ( Base ‘ ∅ ) | 
						
							| 51 | 49 3 50 | 3eqtr4g | ⊢ ( ¬  ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  𝐵  =  ∅ ) | 
						
							| 52 | 51 | mpteq1d | ⊢ ( ¬  ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  ( 𝑚  ∈  𝐵  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) )  =  ( 𝑚  ∈  ∅  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) ) | 
						
							| 53 | 44 52 | eqtr4d | ⊢ ( ¬  ( 𝑁  ∈  V  ∧  𝑅  ∈  V )  →  ( 𝑁  maDet  𝑅 )  =  ( 𝑚  ∈  𝐵  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) ) | 
						
							| 54 | 40 53 | pm2.61i | ⊢ ( 𝑁  maDet  𝑅 )  =  ( 𝑚  ∈  𝐵  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) | 
						
							| 55 | 1 54 | eqtri | ⊢ 𝐷  =  ( 𝑚  ∈  𝐵  ↦  ( 𝑅  Σg  ( 𝑝  ∈  𝑃  ↦  ( ( ( 𝑌  ∘  𝑆 ) ‘ 𝑝 )  ·  ( 𝑈  Σg  ( 𝑥  ∈  𝑁  ↦  ( ( 𝑝 ‘ 𝑥 ) 𝑚 𝑥 ) ) ) ) ) ) ) |