| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isdrngdOLD.b | ⊢ ( 𝜑  →  𝐵  =  ( Base ‘ 𝑅 ) ) | 
						
							| 2 |  | isdrngdOLD.t | ⊢ ( 𝜑  →   ·   =  ( .r ‘ 𝑅 ) ) | 
						
							| 3 |  | isdrngdOLD.z | ⊢ ( 𝜑  →   0   =  ( 0g ‘ 𝑅 ) ) | 
						
							| 4 |  | isdrngdOLD.u | ⊢ ( 𝜑  →   1   =  ( 1r ‘ 𝑅 ) ) | 
						
							| 5 |  | isdrngdOLD.r | ⊢ ( 𝜑  →  𝑅  ∈  Ring ) | 
						
							| 6 |  | isdrngdOLD.n | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  ) )  →  ( 𝑥  ·  𝑦 )  ≠   0  ) | 
						
							| 7 |  | isdrngdOLD.o | ⊢ ( 𝜑  →   1   ≠   0  ) | 
						
							| 8 |  | isdrngdOLD.i | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  𝐼  ∈  𝐵 ) | 
						
							| 9 |  | isdrngdOLD.j | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  𝐼  ≠   0  ) | 
						
							| 10 |  | isdrngdOLD.k | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  ( 𝐼  ·  𝑥 )  =   1  ) | 
						
							| 11 |  | difss | ⊢ ( 𝐵  ∖  {  0  } )  ⊆  𝐵 | 
						
							| 12 | 11 1 | sseqtrid | ⊢ ( 𝜑  →  ( 𝐵  ∖  {  0  } )  ⊆  ( Base ‘ 𝑅 ) ) | 
						
							| 13 |  | eqid | ⊢ ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) )  =  ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) ) | 
						
							| 14 |  | eqid | ⊢ ( mulGrp ‘ 𝑅 )  =  ( mulGrp ‘ 𝑅 ) | 
						
							| 15 |  | eqid | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑅 ) | 
						
							| 16 | 14 15 | mgpbas | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ ( mulGrp ‘ 𝑅 ) ) | 
						
							| 17 | 13 16 | ressbas2 | ⊢ ( ( 𝐵  ∖  {  0  } )  ⊆  ( Base ‘ 𝑅 )  →  ( 𝐵  ∖  {  0  } )  =  ( Base ‘ ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) ) ) ) | 
						
							| 18 | 12 17 | syl | ⊢ ( 𝜑  →  ( 𝐵  ∖  {  0  } )  =  ( Base ‘ ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) ) ) ) | 
						
							| 19 |  | fvex | ⊢ ( Base ‘ 𝑅 )  ∈  V | 
						
							| 20 | 1 19 | eqeltrdi | ⊢ ( 𝜑  →  𝐵  ∈  V ) | 
						
							| 21 |  | difexg | ⊢ ( 𝐵  ∈  V  →  ( 𝐵  ∖  {  0  } )  ∈  V ) | 
						
							| 22 |  | eqid | ⊢ ( .r ‘ 𝑅 )  =  ( .r ‘ 𝑅 ) | 
						
							| 23 | 14 22 | mgpplusg | ⊢ ( .r ‘ 𝑅 )  =  ( +g ‘ ( mulGrp ‘ 𝑅 ) ) | 
						
							| 24 | 13 23 | ressplusg | ⊢ ( ( 𝐵  ∖  {  0  } )  ∈  V  →  ( .r ‘ 𝑅 )  =  ( +g ‘ ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) ) ) ) | 
						
							| 25 | 20 21 24 | 3syl | ⊢ ( 𝜑  →  ( .r ‘ 𝑅 )  =  ( +g ‘ ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) ) ) ) | 
						
							| 26 | 2 25 | eqtrd | ⊢ ( 𝜑  →   ·   =  ( +g ‘ ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) ) ) ) | 
						
							| 27 |  | eldifsn | ⊢ ( 𝑥  ∈  ( 𝐵  ∖  {  0  } )  ↔  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) ) | 
						
							| 28 |  | eldifsn | ⊢ ( 𝑦  ∈  ( 𝐵  ∖  {  0  } )  ↔  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  ) ) | 
						
							| 29 | 15 22 | ringcl | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 ) )  →  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 )  ∈  ( Base ‘ 𝑅 ) ) | 
						
							| 30 | 5 29 | syl3an1 | ⊢ ( ( 𝜑  ∧  𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 ) )  →  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 )  ∈  ( Base ‘ 𝑅 ) ) | 
						
							| 31 | 30 | 3expib | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 ) )  →  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 )  ∈  ( Base ‘ 𝑅 ) ) ) | 
						
							| 32 | 1 | eleq2d | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝐵  ↔  𝑥  ∈  ( Base ‘ 𝑅 ) ) ) | 
						
							| 33 | 1 | eleq2d | ⊢ ( 𝜑  →  ( 𝑦  ∈  𝐵  ↔  𝑦  ∈  ( Base ‘ 𝑅 ) ) ) | 
						
							| 34 | 32 33 | anbi12d | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  ↔  ( 𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 ) ) ) ) | 
						
							| 35 | 2 | oveqd | ⊢ ( 𝜑  →  ( 𝑥  ·  𝑦 )  =  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ) | 
						
							| 36 | 35 1 | eleq12d | ⊢ ( 𝜑  →  ( ( 𝑥  ·  𝑦 )  ∈  𝐵  ↔  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 )  ∈  ( Base ‘ 𝑅 ) ) ) | 
						
							| 37 | 31 34 36 | 3imtr4d | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  →  ( 𝑥  ·  𝑦 )  ∈  𝐵 ) ) | 
						
							| 38 | 37 | 3impib | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  →  ( 𝑥  ·  𝑦 )  ∈  𝐵 ) | 
						
							| 39 | 38 | 3adant2r | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  𝑦  ∈  𝐵 )  →  ( 𝑥  ·  𝑦 )  ∈  𝐵 ) | 
						
							| 40 | 39 | 3adant3r | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  ) )  →  ( 𝑥  ·  𝑦 )  ∈  𝐵 ) | 
						
							| 41 |  | eldifsn | ⊢ ( ( 𝑥  ·  𝑦 )  ∈  ( 𝐵  ∖  {  0  } )  ↔  ( ( 𝑥  ·  𝑦 )  ∈  𝐵  ∧  ( 𝑥  ·  𝑦 )  ≠   0  ) ) | 
						
							| 42 | 40 6 41 | sylanbrc | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  ) )  →  ( 𝑥  ·  𝑦 )  ∈  ( 𝐵  ∖  {  0  } ) ) | 
						
							| 43 | 28 42 | syl3an3b | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  𝑦  ∈  ( 𝐵  ∖  {  0  } ) )  →  ( 𝑥  ·  𝑦 )  ∈  ( 𝐵  ∖  {  0  } ) ) | 
						
							| 44 | 27 43 | syl3an2b | ⊢ ( ( 𝜑  ∧  𝑥  ∈  ( 𝐵  ∖  {  0  } )  ∧  𝑦  ∈  ( 𝐵  ∖  {  0  } ) )  →  ( 𝑥  ·  𝑦 )  ∈  ( 𝐵  ∖  {  0  } ) ) | 
						
							| 45 | 15 22 | ringass | ⊢ ( ( 𝑅  ∈  Ring  ∧  ( 𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 )  ∧  𝑧  ∈  ( Base ‘ 𝑅 ) ) )  →  ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 )  =  ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) | 
						
							| 46 | 45 | ex | ⊢ ( 𝑅  ∈  Ring  →  ( ( 𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 )  ∧  𝑧  ∈  ( Base ‘ 𝑅 ) )  →  ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 )  =  ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) ) | 
						
							| 47 | 5 46 | syl | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 )  ∧  𝑧  ∈  ( Base ‘ 𝑅 ) )  →  ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 )  =  ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) ) | 
						
							| 48 | 1 | eleq2d | ⊢ ( 𝜑  →  ( 𝑧  ∈  𝐵  ↔  𝑧  ∈  ( Base ‘ 𝑅 ) ) ) | 
						
							| 49 | 32 33 48 | 3anbi123d | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵  ∧  𝑧  ∈  𝐵 )  ↔  ( 𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 )  ∧  𝑧  ∈  ( Base ‘ 𝑅 ) ) ) ) | 
						
							| 50 |  | eqidd | ⊢ ( 𝜑  →  𝑧  =  𝑧 ) | 
						
							| 51 | 2 35 50 | oveq123d | ⊢ ( 𝜑  →  ( ( 𝑥  ·  𝑦 )  ·  𝑧 )  =  ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 ) ) | 
						
							| 52 |  | eqidd | ⊢ ( 𝜑  →  𝑥  =  𝑥 ) | 
						
							| 53 | 2 | oveqd | ⊢ ( 𝜑  →  ( 𝑦  ·  𝑧 )  =  ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) | 
						
							| 54 | 2 52 53 | oveq123d | ⊢ ( 𝜑  →  ( 𝑥  ·  ( 𝑦  ·  𝑧 ) )  =  ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) | 
						
							| 55 | 51 54 | eqeq12d | ⊢ ( 𝜑  →  ( ( ( 𝑥  ·  𝑦 )  ·  𝑧 )  =  ( 𝑥  ·  ( 𝑦  ·  𝑧 ) )  ↔  ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 )  =  ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) ) | 
						
							| 56 | 47 49 55 | 3imtr4d | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵  ∧  𝑧  ∈  𝐵 )  →  ( ( 𝑥  ·  𝑦 )  ·  𝑧 )  =  ( 𝑥  ·  ( 𝑦  ·  𝑧 ) ) ) ) | 
						
							| 57 |  | eldifi | ⊢ ( 𝑥  ∈  ( 𝐵  ∖  {  0  } )  →  𝑥  ∈  𝐵 ) | 
						
							| 58 |  | eldifi | ⊢ ( 𝑦  ∈  ( 𝐵  ∖  {  0  } )  →  𝑦  ∈  𝐵 ) | 
						
							| 59 |  | eldifi | ⊢ ( 𝑧  ∈  ( 𝐵  ∖  {  0  } )  →  𝑧  ∈  𝐵 ) | 
						
							| 60 | 57 58 59 | 3anim123i | ⊢ ( ( 𝑥  ∈  ( 𝐵  ∖  {  0  } )  ∧  𝑦  ∈  ( 𝐵  ∖  {  0  } )  ∧  𝑧  ∈  ( 𝐵  ∖  {  0  } ) )  →  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵  ∧  𝑧  ∈  𝐵 ) ) | 
						
							| 61 | 56 60 | impel | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  ( 𝐵  ∖  {  0  } )  ∧  𝑦  ∈  ( 𝐵  ∖  {  0  } )  ∧  𝑧  ∈  ( 𝐵  ∖  {  0  } ) ) )  →  ( ( 𝑥  ·  𝑦 )  ·  𝑧 )  =  ( 𝑥  ·  ( 𝑦  ·  𝑧 ) ) ) | 
						
							| 62 |  | eqid | ⊢ ( 1r ‘ 𝑅 )  =  ( 1r ‘ 𝑅 ) | 
						
							| 63 | 15 62 | ringidcl | ⊢ ( 𝑅  ∈  Ring  →  ( 1r ‘ 𝑅 )  ∈  ( Base ‘ 𝑅 ) ) | 
						
							| 64 | 5 63 | syl | ⊢ ( 𝜑  →  ( 1r ‘ 𝑅 )  ∈  ( Base ‘ 𝑅 ) ) | 
						
							| 65 | 64 4 1 | 3eltr4d | ⊢ ( 𝜑  →   1   ∈  𝐵 ) | 
						
							| 66 |  | eldifsn | ⊢ (  1   ∈  ( 𝐵  ∖  {  0  } )  ↔  (  1   ∈  𝐵  ∧   1   ≠   0  ) ) | 
						
							| 67 | 65 7 66 | sylanbrc | ⊢ ( 𝜑  →   1   ∈  ( 𝐵  ∖  {  0  } ) ) | 
						
							| 68 | 15 22 62 | ringlidm | ⊢ ( ( 𝑅  ∈  Ring  ∧  𝑥  ∈  ( Base ‘ 𝑅 ) )  →  ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 )  =  𝑥 ) | 
						
							| 69 | 68 | ex | ⊢ ( 𝑅  ∈  Ring  →  ( 𝑥  ∈  ( Base ‘ 𝑅 )  →  ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 )  =  𝑥 ) ) | 
						
							| 70 | 5 69 | syl | ⊢ ( 𝜑  →  ( 𝑥  ∈  ( Base ‘ 𝑅 )  →  ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 )  =  𝑥 ) ) | 
						
							| 71 | 2 4 52 | oveq123d | ⊢ ( 𝜑  →  (  1   ·  𝑥 )  =  ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 ) ) | 
						
							| 72 | 71 | eqeq1d | ⊢ ( 𝜑  →  ( (  1   ·  𝑥 )  =  𝑥  ↔  ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 )  =  𝑥 ) ) | 
						
							| 73 | 70 32 72 | 3imtr4d | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝐵  →  (  1   ·  𝑥 )  =  𝑥 ) ) | 
						
							| 74 | 73 | imp | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐵 )  →  (  1   ·  𝑥 )  =  𝑥 ) | 
						
							| 75 | 74 | adantrr | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  (  1   ·  𝑥 )  =  𝑥 ) | 
						
							| 76 | 27 75 | sylan2b | ⊢ ( ( 𝜑  ∧  𝑥  ∈  ( 𝐵  ∖  {  0  } ) )  →  (  1   ·  𝑥 )  =  𝑥 ) | 
						
							| 77 |  | eldifsn | ⊢ ( 𝐼  ∈  ( 𝐵  ∖  {  0  } )  ↔  ( 𝐼  ∈  𝐵  ∧  𝐼  ≠   0  ) ) | 
						
							| 78 | 8 9 77 | sylanbrc | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  𝐼  ∈  ( 𝐵  ∖  {  0  } ) ) | 
						
							| 79 | 27 78 | sylan2b | ⊢ ( ( 𝜑  ∧  𝑥  ∈  ( 𝐵  ∖  {  0  } ) )  →  𝐼  ∈  ( 𝐵  ∖  {  0  } ) ) | 
						
							| 80 | 27 10 | sylan2b | ⊢ ( ( 𝜑  ∧  𝑥  ∈  ( 𝐵  ∖  {  0  } ) )  →  ( 𝐼  ·  𝑥 )  =   1  ) | 
						
							| 81 | 18 26 44 61 67 76 79 80 | isgrpd | ⊢ ( 𝜑  →  ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) )  ∈  Grp ) | 
						
							| 82 | 3 | sneqd | ⊢ ( 𝜑  →  {  0  }  =  { ( 0g ‘ 𝑅 ) } ) | 
						
							| 83 | 1 82 | difeq12d | ⊢ ( 𝜑  →  ( 𝐵  ∖  {  0  } )  =  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) ) | 
						
							| 84 | 83 | oveq2d | ⊢ ( 𝜑  →  ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) )  =  ( ( mulGrp ‘ 𝑅 )  ↾s  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) ) ) | 
						
							| 85 | 84 | eleq1d | ⊢ ( 𝜑  →  ( ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) )  ∈  Grp  ↔  ( ( mulGrp ‘ 𝑅 )  ↾s  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) )  ∈  Grp ) ) | 
						
							| 86 | 85 | anbi2d | ⊢ ( 𝜑  →  ( ( 𝑅  ∈  Ring  ∧  ( ( mulGrp ‘ 𝑅 )  ↾s  ( 𝐵  ∖  {  0  } ) )  ∈  Grp )  ↔  ( 𝑅  ∈  Ring  ∧  ( ( mulGrp ‘ 𝑅 )  ↾s  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) )  ∈  Grp ) ) ) | 
						
							| 87 | 5 81 86 | mpbi2and | ⊢ ( 𝜑  →  ( 𝑅  ∈  Ring  ∧  ( ( mulGrp ‘ 𝑅 )  ↾s  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) )  ∈  Grp ) ) | 
						
							| 88 |  | eqid | ⊢ ( 0g ‘ 𝑅 )  =  ( 0g ‘ 𝑅 ) | 
						
							| 89 |  | eqid | ⊢ ( ( mulGrp ‘ 𝑅 )  ↾s  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) )  =  ( ( mulGrp ‘ 𝑅 )  ↾s  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) ) | 
						
							| 90 | 15 88 89 | isdrng2 | ⊢ ( 𝑅  ∈  DivRing  ↔  ( 𝑅  ∈  Ring  ∧  ( ( mulGrp ‘ 𝑅 )  ↾s  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) )  ∈  Grp ) ) | 
						
							| 91 | 87 90 | sylibr | ⊢ ( 𝜑  →  𝑅  ∈  DivRing ) |