Metamath Proof Explorer
		
		
		
		Description:  The negative of a nonzero number is nonzero.  (Contributed by NM, 30-Jul-2004)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | negidi.1 |  | 
					
						|  |  | negne0i.2 |  | 
				
					|  | Assertion | negne0i |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | negidi.1 |  | 
						
							| 2 |  | negne0i.2 |  | 
						
							| 3 | 1 | negne0bi |  | 
						
							| 4 | 2 3 | mpbi |  |