| Step | Hyp | Ref | Expression | 
						
							| 1 |  | opprbas.1 | ⊢ 𝑂  =  ( oppr ‘ 𝑅 ) | 
						
							| 2 | 1 | opprrng | ⊢ ( 𝑅  ∈  Rng  →  𝑂  ∈  Rng ) | 
						
							| 3 |  | eqid | ⊢ ( oppr ‘ 𝑂 )  =  ( oppr ‘ 𝑂 ) | 
						
							| 4 | 3 | opprrng | ⊢ ( 𝑂  ∈  Rng  →  ( oppr ‘ 𝑂 )  ∈  Rng ) | 
						
							| 5 |  | eqidd | ⊢ ( ⊤  →  ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑅 ) ) | 
						
							| 6 |  | eqid | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑅 ) | 
						
							| 7 | 1 6 | opprbas | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑂 ) | 
						
							| 8 | 3 7 | opprbas | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ ( oppr ‘ 𝑂 ) ) | 
						
							| 9 | 8 | a1i | ⊢ ( ⊤  →  ( Base ‘ 𝑅 )  =  ( Base ‘ ( oppr ‘ 𝑂 ) ) ) | 
						
							| 10 |  | eqid | ⊢ ( +g ‘ 𝑅 )  =  ( +g ‘ 𝑅 ) | 
						
							| 11 | 1 10 | oppradd | ⊢ ( +g ‘ 𝑅 )  =  ( +g ‘ 𝑂 ) | 
						
							| 12 | 3 11 | oppradd | ⊢ ( +g ‘ 𝑅 )  =  ( +g ‘ ( oppr ‘ 𝑂 ) ) | 
						
							| 13 | 12 | oveqi | ⊢ ( 𝑥 ( +g ‘ 𝑅 ) 𝑦 )  =  ( 𝑥 ( +g ‘ ( oppr ‘ 𝑂 ) ) 𝑦 ) | 
						
							| 14 | 13 | a1i | ⊢ ( ( ⊤  ∧  ( 𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 ) ) )  →  ( 𝑥 ( +g ‘ 𝑅 ) 𝑦 )  =  ( 𝑥 ( +g ‘ ( oppr ‘ 𝑂 ) ) 𝑦 ) ) | 
						
							| 15 |  | eqid | ⊢ ( .r ‘ 𝑂 )  =  ( .r ‘ 𝑂 ) | 
						
							| 16 |  | eqid | ⊢ ( .r ‘ ( oppr ‘ 𝑂 ) )  =  ( .r ‘ ( oppr ‘ 𝑂 ) ) | 
						
							| 17 | 7 15 3 16 | opprmul | ⊢ ( 𝑥 ( .r ‘ ( oppr ‘ 𝑂 ) ) 𝑦 )  =  ( 𝑦 ( .r ‘ 𝑂 ) 𝑥 ) | 
						
							| 18 |  | eqid | ⊢ ( .r ‘ 𝑅 )  =  ( .r ‘ 𝑅 ) | 
						
							| 19 | 6 18 1 15 | opprmul | ⊢ ( 𝑦 ( .r ‘ 𝑂 ) 𝑥 )  =  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) | 
						
							| 20 | 17 19 | eqtr2i | ⊢ ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 )  =  ( 𝑥 ( .r ‘ ( oppr ‘ 𝑂 ) ) 𝑦 ) | 
						
							| 21 | 20 | a1i | ⊢ ( ( ⊤  ∧  ( 𝑥  ∈  ( Base ‘ 𝑅 )  ∧  𝑦  ∈  ( Base ‘ 𝑅 ) ) )  →  ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 )  =  ( 𝑥 ( .r ‘ ( oppr ‘ 𝑂 ) ) 𝑦 ) ) | 
						
							| 22 | 5 9 14 21 | rngpropd | ⊢ ( ⊤  →  ( 𝑅  ∈  Rng  ↔  ( oppr ‘ 𝑂 )  ∈  Rng ) ) | 
						
							| 23 | 22 | mptru | ⊢ ( 𝑅  ∈  Rng  ↔  ( oppr ‘ 𝑂 )  ∈  Rng ) | 
						
							| 24 | 4 23 | sylibr | ⊢ ( 𝑂  ∈  Rng  →  𝑅  ∈  Rng ) | 
						
							| 25 | 2 24 | impbii | ⊢ ( 𝑅  ∈  Rng  ↔  𝑂  ∈  Rng ) |