Metamath Proof Explorer
		
		
		
		Description:  The involution function in a star ring is an antiautomorphism.
       (Contributed by Mario Carneiro, 6-Oct-2015)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | issrng.o | ⊢ 𝑂  =  ( oppr ‘ 𝑅 ) | 
					
						|  |  | issrng.i | ⊢  ∗   =  ( *rf ‘ 𝑅 ) | 
				
					|  | Assertion | srngrhm | ⊢  ( 𝑅  ∈  *-Ring  →   ∗   ∈  ( 𝑅  RingHom  𝑂 ) ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | issrng.o | ⊢ 𝑂  =  ( oppr ‘ 𝑅 ) | 
						
							| 2 |  | issrng.i | ⊢  ∗   =  ( *rf ‘ 𝑅 ) | 
						
							| 3 | 1 2 | issrng | ⊢ ( 𝑅  ∈  *-Ring  ↔  (  ∗   ∈  ( 𝑅  RingHom  𝑂 )  ∧   ∗   =  ◡  ∗  ) ) | 
						
							| 4 | 3 | simplbi | ⊢ ( 𝑅  ∈  *-Ring  →   ∗   ∈  ( 𝑅  RingHom  𝑂 ) ) |