| 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 |  | isdrngrdOLD.k | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  ( 𝑥  ·  𝐼 )  =   1  ) | 
						
							| 11 |  | eqid | ⊢ ( oppr ‘ 𝑅 )  =  ( oppr ‘ 𝑅 ) | 
						
							| 12 |  | eqid | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑅 ) | 
						
							| 13 | 11 12 | opprbas | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ ( oppr ‘ 𝑅 ) ) | 
						
							| 14 | 1 13 | eqtrdi | ⊢ ( 𝜑  →  𝐵  =  ( Base ‘ ( oppr ‘ 𝑅 ) ) ) | 
						
							| 15 |  | eqidd | ⊢ ( 𝜑  →  ( .r ‘ ( oppr ‘ 𝑅 ) )  =  ( .r ‘ ( oppr ‘ 𝑅 ) ) ) | 
						
							| 16 |  | eqid | ⊢ ( 0g ‘ 𝑅 )  =  ( 0g ‘ 𝑅 ) | 
						
							| 17 | 11 16 | oppr0 | ⊢ ( 0g ‘ 𝑅 )  =  ( 0g ‘ ( oppr ‘ 𝑅 ) ) | 
						
							| 18 | 3 17 | eqtrdi | ⊢ ( 𝜑  →   0   =  ( 0g ‘ ( oppr ‘ 𝑅 ) ) ) | 
						
							| 19 |  | eqid | ⊢ ( 1r ‘ 𝑅 )  =  ( 1r ‘ 𝑅 ) | 
						
							| 20 | 11 19 | oppr1 | ⊢ ( 1r ‘ 𝑅 )  =  ( 1r ‘ ( oppr ‘ 𝑅 ) ) | 
						
							| 21 | 4 20 | eqtrdi | ⊢ ( 𝜑  →   1   =  ( 1r ‘ ( oppr ‘ 𝑅 ) ) ) | 
						
							| 22 | 11 | opprring | ⊢ ( 𝑅  ∈  Ring  →  ( oppr ‘ 𝑅 )  ∈  Ring ) | 
						
							| 23 | 5 22 | syl | ⊢ ( 𝜑  →  ( oppr ‘ 𝑅 )  ∈  Ring ) | 
						
							| 24 |  | eleq1w | ⊢ ( 𝑦  =  𝑥  →  ( 𝑦  ∈  𝐵  ↔  𝑥  ∈  𝐵 ) ) | 
						
							| 25 |  | neeq1 | ⊢ ( 𝑦  =  𝑥  →  ( 𝑦  ≠   0   ↔  𝑥  ≠   0  ) ) | 
						
							| 26 | 24 25 | anbi12d | ⊢ ( 𝑦  =  𝑥  →  ( ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ↔  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) ) ) | 
						
							| 27 | 26 | 3anbi2d | ⊢ ( 𝑦  =  𝑥  →  ( ( 𝜑  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ∧  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) )  ↔  ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) ) ) ) | 
						
							| 28 |  | oveq1 | ⊢ ( 𝑦  =  𝑥  →  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  =  ( 𝑥 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 ) ) | 
						
							| 29 | 28 | neeq1d | ⊢ ( 𝑦  =  𝑥  →  ( ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  ≠   0   ↔  ( 𝑥 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  ≠   0  ) ) | 
						
							| 30 | 27 29 | imbi12d | ⊢ ( 𝑦  =  𝑥  →  ( ( ( 𝜑  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ∧  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) )  →  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  ≠   0  )  ↔  ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) )  →  ( 𝑥 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  ≠   0  ) ) ) | 
						
							| 31 |  | eleq1w | ⊢ ( 𝑥  =  𝑧  →  ( 𝑥  ∈  𝐵  ↔  𝑧  ∈  𝐵 ) ) | 
						
							| 32 |  | neeq1 | ⊢ ( 𝑥  =  𝑧  →  ( 𝑥  ≠   0   ↔  𝑧  ≠   0  ) ) | 
						
							| 33 | 31 32 | anbi12d | ⊢ ( 𝑥  =  𝑧  →  ( ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ↔  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) ) ) | 
						
							| 34 | 33 | 3anbi3d | ⊢ ( 𝑥  =  𝑧  →  ( ( 𝜑  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  ↔  ( 𝜑  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ∧  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) ) ) ) | 
						
							| 35 |  | oveq2 | ⊢ ( 𝑥  =  𝑧  →  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 )  =  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 ) ) | 
						
							| 36 | 35 | neeq1d | ⊢ ( 𝑥  =  𝑧  →  ( ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 )  ≠   0   ↔  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  ≠   0  ) ) | 
						
							| 37 | 34 36 | imbi12d | ⊢ ( 𝑥  =  𝑧  →  ( ( ( 𝜑  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 )  ≠   0  )  ↔  ( ( 𝜑  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ∧  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) )  →  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  ≠   0  ) ) ) | 
						
							| 38 | 2 | 3ad2ant1 | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  ) )  →   ·   =  ( .r ‘ 𝑅 ) ) | 
						
							| 39 | 38 | oveqd | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  ) )  →  ( 𝑥  ·  𝑦 )  =  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ) | 
						
							| 40 |  | eqid | ⊢ ( .r ‘ 𝑅 )  =  ( .r ‘ 𝑅 ) | 
						
							| 41 |  | eqid | ⊢ ( .r ‘ ( oppr ‘ 𝑅 ) )  =  ( .r ‘ ( oppr ‘ 𝑅 ) ) | 
						
							| 42 | 12 40 11 41 | opprmul | ⊢ ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 )  =  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) | 
						
							| 43 | 39 42 | eqtr4di | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  ) )  →  ( 𝑥  ·  𝑦 )  =  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 ) ) | 
						
							| 44 | 43 6 | eqnetrrd | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  ) )  →  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 )  ≠   0  ) | 
						
							| 45 | 44 | 3com23 | ⊢ ( ( 𝜑  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 )  ≠   0  ) | 
						
							| 46 | 37 45 | chvarvv | ⊢ ( ( 𝜑  ∧  ( 𝑦  ∈  𝐵  ∧  𝑦  ≠   0  )  ∧  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) )  →  ( 𝑦 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  ≠   0  ) | 
						
							| 47 | 30 46 | chvarvv | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  )  ∧  ( 𝑧  ∈  𝐵  ∧  𝑧  ≠   0  ) )  →  ( 𝑥 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑧 )  ≠   0  ) | 
						
							| 48 | 12 40 11 41 | opprmul | ⊢ ( 𝐼 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 )  =  ( 𝑥 ( .r ‘ 𝑅 ) 𝐼 ) | 
						
							| 49 | 2 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →   ·   =  ( .r ‘ 𝑅 ) ) | 
						
							| 50 | 49 | oveqd | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  ( 𝑥  ·  𝐼 )  =  ( 𝑥 ( .r ‘ 𝑅 ) 𝐼 ) ) | 
						
							| 51 | 50 10 | eqtr3d | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  ( 𝑥 ( .r ‘ 𝑅 ) 𝐼 )  =   1  ) | 
						
							| 52 | 48 51 | eqtrid | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑥  ≠   0  ) )  →  ( 𝐼 ( .r ‘ ( oppr ‘ 𝑅 ) ) 𝑥 )  =   1  ) | 
						
							| 53 | 14 15 18 21 23 47 7 8 9 52 | isdrngdOLD | ⊢ ( 𝜑  →  ( oppr ‘ 𝑅 )  ∈  DivRing ) | 
						
							| 54 | 11 | opprdrng | ⊢ ( 𝑅  ∈  DivRing  ↔  ( oppr ‘ 𝑅 )  ∈  DivRing ) | 
						
							| 55 | 53 54 | sylibr | ⊢ ( 𝜑  →  𝑅  ∈  DivRing ) |