| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdetuni.a | ⊢ 𝐴  =  ( 𝑁  Mat  𝑅 ) | 
						
							| 2 |  | mdetuni.b | ⊢ 𝐵  =  ( Base ‘ 𝐴 ) | 
						
							| 3 |  | mdetuni.k | ⊢ 𝐾  =  ( Base ‘ 𝑅 ) | 
						
							| 4 |  | mdetuni.0g | ⊢  0   =  ( 0g ‘ 𝑅 ) | 
						
							| 5 |  | mdetuni.1r | ⊢  1   =  ( 1r ‘ 𝑅 ) | 
						
							| 6 |  | mdetuni.pg | ⊢  +   =  ( +g ‘ 𝑅 ) | 
						
							| 7 |  | mdetuni.tg | ⊢  ·   =  ( .r ‘ 𝑅 ) | 
						
							| 8 |  | mdetuni.n | ⊢ ( 𝜑  →  𝑁  ∈  Fin ) | 
						
							| 9 |  | mdetuni.r | ⊢ ( 𝜑  →  𝑅  ∈  Ring ) | 
						
							| 10 |  | mdetuni.ff | ⊢ ( 𝜑  →  𝐷 : 𝐵 ⟶ 𝐾 ) | 
						
							| 11 |  | mdetuni.al | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝑁 ∀ 𝑧  ∈  𝑁 ( ( 𝑦  ≠  𝑧  ∧  ∀ 𝑤  ∈  𝑁 ( 𝑦 𝑥 𝑤 )  =  ( 𝑧 𝑥 𝑤 ) )  →  ( 𝐷 ‘ 𝑥 )  =   0  ) ) | 
						
							| 12 |  | mdetuni.li | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐵 ∀ 𝑧  ∈  𝐵 ∀ 𝑤  ∈  𝑁 ( ( ( 𝑥  ↾  ( { 𝑤 }  ×  𝑁 ) )  =  ( ( 𝑦  ↾  ( { 𝑤 }  ×  𝑁 ) )  ∘f   +  ( 𝑧  ↾  ( { 𝑤 }  ×  𝑁 ) ) )  ∧  ( 𝑥  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) )  =  ( 𝑦  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) )  ∧  ( 𝑥  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) )  =  ( 𝑧  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) ) )  →  ( 𝐷 ‘ 𝑥 )  =  ( ( 𝐷 ‘ 𝑦 )  +  ( 𝐷 ‘ 𝑧 ) ) ) ) | 
						
							| 13 |  | mdetuni.sc | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐵 ∀ 𝑦  ∈  𝐾 ∀ 𝑧  ∈  𝐵 ∀ 𝑤  ∈  𝑁 ( ( ( 𝑥  ↾  ( { 𝑤 }  ×  𝑁 ) )  =  ( ( ( { 𝑤 }  ×  𝑁 )  ×  { 𝑦 } )  ∘f   ·  ( 𝑧  ↾  ( { 𝑤 }  ×  𝑁 ) ) )  ∧  ( 𝑥  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) )  =  ( 𝑧  ↾  ( ( 𝑁  ∖  { 𝑤 } )  ×  𝑁 ) ) )  →  ( 𝐷 ‘ 𝑥 )  =  ( 𝑦  ·  ( 𝐷 ‘ 𝑧 ) ) ) ) | 
						
							| 14 |  | mdetunilem8.id | ⊢ ( 𝜑  →  ( 𝐷 ‘ ( 1r ‘ 𝐴 ) )  =   0  ) | 
						
							| 15 |  | simpl | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  𝜑 ) | 
						
							| 16 |  | enrefg | ⊢ ( 𝑁  ∈  Fin  →  𝑁  ≈  𝑁 ) | 
						
							| 17 | 8 16 | syl | ⊢ ( 𝜑  →  𝑁  ≈  𝑁 ) | 
						
							| 18 |  | f1finf1o | ⊢ ( ( 𝑁  ≈  𝑁  ∧  𝑁  ∈  Fin )  →  ( 𝐸 : 𝑁 –1-1→ 𝑁  ↔  𝐸 : 𝑁 –1-1-onto→ 𝑁 ) ) | 
						
							| 19 | 17 8 18 | syl2anc | ⊢ ( 𝜑  →  ( 𝐸 : 𝑁 –1-1→ 𝑁  ↔  𝐸 : 𝑁 –1-1-onto→ 𝑁 ) ) | 
						
							| 20 | 19 | biimpa | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  𝐸 : 𝑁 –1-1-onto→ 𝑁 ) | 
						
							| 21 | 1 | matring | ⊢ ( ( 𝑁  ∈  Fin  ∧  𝑅  ∈  Ring )  →  𝐴  ∈  Ring ) | 
						
							| 22 | 8 9 21 | syl2anc | ⊢ ( 𝜑  →  𝐴  ∈  Ring ) | 
						
							| 23 |  | eqid | ⊢ ( 1r ‘ 𝐴 )  =  ( 1r ‘ 𝐴 ) | 
						
							| 24 | 2 23 | ringidcl | ⊢ ( 𝐴  ∈  Ring  →  ( 1r ‘ 𝐴 )  ∈  𝐵 ) | 
						
							| 25 | 22 24 | syl | ⊢ ( 𝜑  →  ( 1r ‘ 𝐴 )  ∈  𝐵 ) | 
						
							| 26 | 25 | adantr | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( 1r ‘ 𝐴 )  ∈  𝐵 ) | 
						
							| 27 | 1 2 3 4 5 6 7 8 9 10 11 12 13 | mdetunilem7 | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1-onto→ 𝑁  ∧  ( 1r ‘ 𝐴 )  ∈  𝐵 )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  ( ( 𝐸 ‘ 𝑎 ) ( 1r ‘ 𝐴 ) 𝑏 ) ) )  =  ( ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ·  ( 𝐷 ‘ ( 1r ‘ 𝐴 ) ) ) ) | 
						
							| 28 | 15 20 26 27 | syl3anc | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  ( ( 𝐸 ‘ 𝑎 ) ( 1r ‘ 𝐴 ) 𝑏 ) ) )  =  ( ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ·  ( 𝐷 ‘ ( 1r ‘ 𝐴 ) ) ) ) | 
						
							| 29 | 8 | adantr | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  𝑁  ∈  Fin ) | 
						
							| 30 | 29 | 3ad2ant1 | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝑁  ∈  Fin ) | 
						
							| 31 | 9 | adantr | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  𝑅  ∈  Ring ) | 
						
							| 32 | 31 | 3ad2ant1 | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝑅  ∈  Ring ) | 
						
							| 33 |  | simp1r | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝐸 : 𝑁 –1-1→ 𝑁 ) | 
						
							| 34 |  | f1f | ⊢ ( 𝐸 : 𝑁 –1-1→ 𝑁  →  𝐸 : 𝑁 ⟶ 𝑁 ) | 
						
							| 35 | 33 34 | syl | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝐸 : 𝑁 ⟶ 𝑁 ) | 
						
							| 36 |  | simp2 | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝑎  ∈  𝑁 ) | 
						
							| 37 | 35 36 | ffvelcdmd | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  ( 𝐸 ‘ 𝑎 )  ∈  𝑁 ) | 
						
							| 38 |  | simp3 | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝑏  ∈  𝑁 ) | 
						
							| 39 | 1 5 4 30 32 37 38 23 | mat1ov | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  ( ( 𝐸 ‘ 𝑎 ) ( 1r ‘ 𝐴 ) 𝑏 )  =  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) | 
						
							| 40 | 39 | mpoeq3dva | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  ( ( 𝐸 ‘ 𝑎 ) ( 1r ‘ 𝐴 ) 𝑏 ) )  =  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) | 
						
							| 41 | 40 | fveq2d | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  ( ( 𝐸 ‘ 𝑎 ) ( 1r ‘ 𝐴 ) 𝑏 ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) | 
						
							| 42 | 14 | adantr | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( 𝐷 ‘ ( 1r ‘ 𝐴 ) )  =   0  ) | 
						
							| 43 | 42 | oveq2d | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ·  ( 𝐷 ‘ ( 1r ‘ 𝐴 ) ) )  =  ( ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ·   0  ) ) | 
						
							| 44 |  | zrhpsgnmhm | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝑁  ∈  Fin )  →  ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) )  ∈  ( ( SymGrp ‘ 𝑁 )  MndHom  ( mulGrp ‘ 𝑅 ) ) ) | 
						
							| 45 | 9 8 44 | syl2anc | ⊢ ( 𝜑  →  ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) )  ∈  ( ( SymGrp ‘ 𝑁 )  MndHom  ( mulGrp ‘ 𝑅 ) ) ) | 
						
							| 46 |  | eqid | ⊢ ( Base ‘ ( SymGrp ‘ 𝑁 ) )  =  ( Base ‘ ( SymGrp ‘ 𝑁 ) ) | 
						
							| 47 |  | eqid | ⊢ ( mulGrp ‘ 𝑅 )  =  ( mulGrp ‘ 𝑅 ) | 
						
							| 48 | 47 3 | mgpbas | ⊢ 𝐾  =  ( Base ‘ ( mulGrp ‘ 𝑅 ) ) | 
						
							| 49 | 46 48 | mhmf | ⊢ ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) )  ∈  ( ( SymGrp ‘ 𝑁 )  MndHom  ( mulGrp ‘ 𝑅 ) )  →  ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) : ( Base ‘ ( SymGrp ‘ 𝑁 ) ) ⟶ 𝐾 ) | 
						
							| 50 | 45 49 | syl | ⊢ ( 𝜑  →  ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) : ( Base ‘ ( SymGrp ‘ 𝑁 ) ) ⟶ 𝐾 ) | 
						
							| 51 | 50 | adantr | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) : ( Base ‘ ( SymGrp ‘ 𝑁 ) ) ⟶ 𝐾 ) | 
						
							| 52 |  | eqid | ⊢ ( SymGrp ‘ 𝑁 )  =  ( SymGrp ‘ 𝑁 ) | 
						
							| 53 | 52 46 | elsymgbas | ⊢ ( 𝑁  ∈  Fin  →  ( 𝐸  ∈  ( Base ‘ ( SymGrp ‘ 𝑁 ) )  ↔  𝐸 : 𝑁 –1-1-onto→ 𝑁 ) ) | 
						
							| 54 | 29 53 | syl | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( 𝐸  ∈  ( Base ‘ ( SymGrp ‘ 𝑁 ) )  ↔  𝐸 : 𝑁 –1-1-onto→ 𝑁 ) ) | 
						
							| 55 | 20 54 | mpbird | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  𝐸  ∈  ( Base ‘ ( SymGrp ‘ 𝑁 ) ) ) | 
						
							| 56 | 51 55 | ffvelcdmd | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ∈  𝐾 ) | 
						
							| 57 | 3 7 4 | ringrz | ⊢ ( ( 𝑅  ∈  Ring  ∧  ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ∈  𝐾 )  →  ( ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ·   0  )  =   0  ) | 
						
							| 58 | 31 56 57 | syl2anc | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ·   0  )  =   0  ) | 
						
							| 59 | 43 58 | eqtrd | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( ( ( ( ℤRHom ‘ 𝑅 )  ∘  ( pmSgn ‘ 𝑁 ) ) ‘ 𝐸 )  ·  ( 𝐷 ‘ ( 1r ‘ 𝐴 ) ) )  =   0  ) | 
						
							| 60 | 28 41 59 | 3eqtr3d | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 –1-1→ 𝑁 )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =   0  ) | 
						
							| 61 | 60 | ex | ⊢ ( 𝜑  →  ( 𝐸 : 𝑁 –1-1→ 𝑁  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =   0  ) ) | 
						
							| 62 | 61 | adantr | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  →  ( 𝐸 : 𝑁 –1-1→ 𝑁  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =   0  ) ) | 
						
							| 63 |  | dff13 | ⊢ ( 𝐸 : 𝑁 –1-1→ 𝑁  ↔  ( 𝐸 : 𝑁 ⟶ 𝑁  ∧  ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 ) ) ) | 
						
							| 64 |  | ibar | ⊢ ( 𝐸 : 𝑁 ⟶ 𝑁  →  ( ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ( 𝐸 : 𝑁 ⟶ 𝑁  ∧  ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 ) ) ) ) | 
						
							| 65 | 64 | adantl | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  →  ( ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ( 𝐸 : 𝑁 ⟶ 𝑁  ∧  ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 ) ) ) ) | 
						
							| 66 | 63 65 | bitr4id | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  →  ( 𝐸 : 𝑁 –1-1→ 𝑁  ↔  ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 ) ) ) | 
						
							| 67 | 66 | notbid | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  →  ( ¬  𝐸 : 𝑁 –1-1→ 𝑁  ↔  ¬  ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 ) ) ) | 
						
							| 68 |  | rexnal | ⊢ ( ∃ 𝑐  ∈  𝑁 ¬  ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ¬  ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 ) ) | 
						
							| 69 |  | rexnal | ⊢ ( ∃ 𝑑  ∈  𝑁 ¬  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ¬  ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 ) ) | 
						
							| 70 |  | df-ne | ⊢ ( 𝑐  ≠  𝑑  ↔  ¬  𝑐  =  𝑑 ) | 
						
							| 71 | 70 | anbi2i | ⊢ ( ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 )  ↔  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  ¬  𝑐  =  𝑑 ) ) | 
						
							| 72 |  | annim | ⊢ ( ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  ¬  𝑐  =  𝑑 )  ↔  ¬  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 ) ) | 
						
							| 73 | 71 72 | bitr2i | ⊢ ( ¬  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) | 
						
							| 74 | 73 | rexbii | ⊢ ( ∃ 𝑑  ∈  𝑁 ¬  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ∃ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) | 
						
							| 75 | 69 74 | bitr3i | ⊢ ( ¬  ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ∃ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) | 
						
							| 76 | 75 | rexbii | ⊢ ( ∃ 𝑐  ∈  𝑁 ¬  ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ∃ 𝑐  ∈  𝑁 ∃ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) | 
						
							| 77 | 68 76 | bitr3i | ⊢ ( ¬  ∀ 𝑐  ∈  𝑁 ∀ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  𝑐  =  𝑑 )  ↔  ∃ 𝑐  ∈  𝑁 ∃ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) | 
						
							| 78 | 67 77 | bitrdi | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  →  ( ¬  𝐸 : 𝑁 –1-1→ 𝑁  ↔  ∃ 𝑐  ∈  𝑁 ∃ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) ) | 
						
							| 79 |  | simprrl | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 ) ) | 
						
							| 80 |  | fveqeq2 | ⊢ ( 𝑎  =  𝑐  →  ( ( 𝐸 ‘ 𝑎 )  =  𝑏  ↔  ( 𝐸 ‘ 𝑐 )  =  𝑏 ) ) | 
						
							| 81 | 80 | ifbid | ⊢ ( 𝑎  =  𝑐  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ) | 
						
							| 82 |  | iftrue | ⊢ ( 𝑎  =  𝑐  →  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ) | 
						
							| 83 | 81 82 | eqtr4d | ⊢ ( 𝑎  =  𝑐  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) | 
						
							| 84 |  | fveqeq2 | ⊢ ( 𝑎  =  𝑑  →  ( ( 𝐸 ‘ 𝑎 )  =  𝑏  ↔  ( 𝐸 ‘ 𝑑 )  =  𝑏 ) ) | 
						
							| 85 | 84 | ifbid | ⊢ ( 𝑎  =  𝑑  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ) | 
						
							| 86 |  | iftrue | ⊢ ( 𝑎  =  𝑑  →  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) )  =  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ) | 
						
							| 87 | 85 86 | eqtr4d | ⊢ ( 𝑎  =  𝑑  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) | 
						
							| 88 |  | iffalse | ⊢ ( ¬  𝑎  =  𝑑  →  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) )  =  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) | 
						
							| 89 | 88 | eqcomd | ⊢ ( ¬  𝑎  =  𝑑  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) | 
						
							| 90 | 87 89 | pm2.61i | ⊢ if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) | 
						
							| 91 |  | iffalse | ⊢ ( ¬  𝑎  =  𝑐  →  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) | 
						
							| 92 | 90 91 | eqtr4id | ⊢ ( ¬  𝑎  =  𝑐  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) | 
						
							| 93 | 83 92 | pm2.61i | ⊢ if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) | 
						
							| 94 |  | eqeq1 | ⊢ ( ( 𝐸 ‘ 𝑑 )  =  ( 𝐸 ‘ 𝑐 )  →  ( ( 𝐸 ‘ 𝑑 )  =  𝑏  ↔  ( 𝐸 ‘ 𝑐 )  =  𝑏 ) ) | 
						
							| 95 | 94 | eqcoms | ⊢ ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  ( ( 𝐸 ‘ 𝑑 )  =  𝑏  ↔  ( 𝐸 ‘ 𝑐 )  =  𝑏 ) ) | 
						
							| 96 | 95 | ifbid | ⊢ ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  )  =  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ) | 
						
							| 97 | 96 | ifeq1d | ⊢ ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) )  =  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) | 
						
							| 98 | 97 | ifeq2d | ⊢ ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑑 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) | 
						
							| 99 | 93 98 | eqtrid | ⊢ ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  =  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) | 
						
							| 100 | 99 | mpoeq3dv | ⊢ ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) )  =  ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) ) | 
						
							| 101 | 100 | fveq2d | ⊢ ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) ) ) | 
						
							| 102 | 79 101 | syl | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) ) ) | 
						
							| 103 |  | simpll | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  𝜑 ) | 
						
							| 104 |  | simprll | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  𝑐  ∈  𝑁 ) | 
						
							| 105 |  | simprlr | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  𝑑  ∈  𝑁 ) | 
						
							| 106 |  | simprrr | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  𝑐  ≠  𝑑 ) | 
						
							| 107 | 104 105 106 | 3jca | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁  ∧  𝑐  ≠  𝑑 ) ) | 
						
							| 108 | 3 5 | ringidcl | ⊢ ( 𝑅  ∈  Ring  →   1   ∈  𝐾 ) | 
						
							| 109 | 9 108 | syl | ⊢ ( 𝜑  →   1   ∈  𝐾 ) | 
						
							| 110 | 3 4 | ring0cl | ⊢ ( 𝑅  ∈  Ring  →   0   ∈  𝐾 ) | 
						
							| 111 | 9 110 | syl | ⊢ ( 𝜑  →   0   ∈  𝐾 ) | 
						
							| 112 | 109 111 | ifcld | ⊢ ( 𝜑  →  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  )  ∈  𝐾 ) | 
						
							| 113 | 112 | ad3antrrr | ⊢ ( ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  ∧  𝑏  ∈  𝑁 )  →  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  )  ∈  𝐾 ) | 
						
							| 114 |  | simp1ll | ⊢ ( ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  𝜑 ) | 
						
							| 115 | 109 111 | ifcld | ⊢ ( 𝜑  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  ∈  𝐾 ) | 
						
							| 116 | 114 115 | syl | ⊢ ( ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  ∧  𝑎  ∈  𝑁  ∧  𝑏  ∈  𝑁 )  →  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  )  ∈  𝐾 ) | 
						
							| 117 | 1 2 3 4 5 6 7 8 9 10 11 12 13 103 107 113 116 | mdetunilem2 | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( 𝑎  =  𝑐 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( 𝑎  =  𝑑 ,  if ( ( 𝐸 ‘ 𝑐 )  =  𝑏 ,   1  ,   0  ) ,  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) ) ) )  =   0  ) | 
						
							| 118 | 102 117 | eqtrd | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 )  ∧  ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 ) ) )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =   0  ) | 
						
							| 119 | 118 | expr | ⊢ ( ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  ∧  ( 𝑐  ∈  𝑁  ∧  𝑑  ∈  𝑁 ) )  →  ( ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =   0  ) ) | 
						
							| 120 | 119 | rexlimdvva | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  →  ( ∃ 𝑐  ∈  𝑁 ∃ 𝑑  ∈  𝑁 ( ( 𝐸 ‘ 𝑐 )  =  ( 𝐸 ‘ 𝑑 )  ∧  𝑐  ≠  𝑑 )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =   0  ) ) | 
						
							| 121 | 78 120 | sylbid | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  →  ( ¬  𝐸 : 𝑁 –1-1→ 𝑁  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =   0  ) ) | 
						
							| 122 | 62 121 | pm2.61d | ⊢ ( ( 𝜑  ∧  𝐸 : 𝑁 ⟶ 𝑁 )  →  ( 𝐷 ‘ ( 𝑎  ∈  𝑁 ,  𝑏  ∈  𝑁  ↦  if ( ( 𝐸 ‘ 𝑎 )  =  𝑏 ,   1  ,   0  ) ) )  =   0  ) |