| Step | Hyp | Ref | Expression | 
						
							| 1 |  | rhmf1o.b | ⊢ 𝐵  =  ( Base ‘ 𝑅 ) | 
						
							| 2 |  | rhmf1o.c | ⊢ 𝐶  =  ( Base ‘ 𝑆 ) | 
						
							| 3 |  | isrim0OLD | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑆  ∈  𝑊 )  →  ( 𝐹  ∈  ( 𝑅  RingIso  𝑆 )  ↔  ( 𝐹  ∈  ( 𝑅  RingHom  𝑆 )  ∧  ◡ 𝐹  ∈  ( 𝑆  RingHom  𝑅 ) ) ) ) | 
						
							| 4 | 1 2 | rhmf1o | ⊢ ( 𝐹  ∈  ( 𝑅  RingHom  𝑆 )  →  ( 𝐹 : 𝐵 –1-1-onto→ 𝐶  ↔  ◡ 𝐹  ∈  ( 𝑆  RingHom  𝑅 ) ) ) | 
						
							| 5 | 4 | bicomd | ⊢ ( 𝐹  ∈  ( 𝑅  RingHom  𝑆 )  →  ( ◡ 𝐹  ∈  ( 𝑆  RingHom  𝑅 )  ↔  𝐹 : 𝐵 –1-1-onto→ 𝐶 ) ) | 
						
							| 6 | 5 | a1i | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑆  ∈  𝑊 )  →  ( 𝐹  ∈  ( 𝑅  RingHom  𝑆 )  →  ( ◡ 𝐹  ∈  ( 𝑆  RingHom  𝑅 )  ↔  𝐹 : 𝐵 –1-1-onto→ 𝐶 ) ) ) | 
						
							| 7 | 6 | pm5.32d | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑆  ∈  𝑊 )  →  ( ( 𝐹  ∈  ( 𝑅  RingHom  𝑆 )  ∧  ◡ 𝐹  ∈  ( 𝑆  RingHom  𝑅 ) )  ↔  ( 𝐹  ∈  ( 𝑅  RingHom  𝑆 )  ∧  𝐹 : 𝐵 –1-1-onto→ 𝐶 ) ) ) | 
						
							| 8 | 3 7 | bitrd | ⊢ ( ( 𝑅  ∈  𝑉  ∧  𝑆  ∈  𝑊 )  →  ( 𝐹  ∈  ( 𝑅  RingIso  𝑆 )  ↔  ( 𝐹  ∈  ( 𝑅  RingHom  𝑆 )  ∧  𝐹 : 𝐵 –1-1-onto→ 𝐶 ) ) ) |