Metamath Proof Explorer
		
		
		
		Description:  The ZRHom homomorphism is a homomorphism.  (Contributed by Mario
       Carneiro, 12-Jun-2015)  (Revised by AV, 12-Jun-2019)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypothesis | zrhval.l |  | 
				
					|  | Assertion | zrhrhm |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | zrhval.l |  | 
						
							| 2 |  | eqid |  | 
						
							| 3 | 1 | zrhrhmb |  | 
						
							| 4 | 2 3 | mpbiri |  |