Metamath Proof Explorer
		
		
		
		Description:  The cardinality of a set is greater than or equal to zero.  (Contributed by Thierry Arnoux, 2-Mar-2017)
		
			
				
					|  |  | Ref | Expression | 
				
					|  | Assertion | hashge0 |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 0domg |  | 
						
							| 2 |  | hashdomi |  | 
						
							| 3 |  | hash0 |  | 
						
							| 4 | 3 | breq1i |  | 
						
							| 5 | 4 | biimpi |  | 
						
							| 6 | 1 2 5 | 3syl |  |