Metamath Proof Explorer
		
		
		
		Description:  The multiplication operation of the ring of integers.  (Contributed by Thierry Arnoux, 1-Nov-2017)  (Revised by AV, 9-Jun-2019)
		
			
				
					|  |  | Ref | Expression | 
				
					|  | Assertion | zringmulr |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | zex |  | 
						
							| 2 |  | df-zring |  | 
						
							| 3 |  | cnfldmul |  | 
						
							| 4 | 2 3 | ressmulr |  | 
						
							| 5 | 1 4 | ax-mp |  |