Metamath Proof Explorer
		
		
		
		Description:  First-order logic and set theory.  (Contributed by Jonathan Ben-Naim, 3-Jun-2011)  (New usage is discouraged.)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypothesis | bnj1196.1 |  | 
				
					|  | Assertion | bnj1196 |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | bnj1196.1 |  | 
						
							| 2 |  | df-rex |  | 
						
							| 3 | 1 2 | sylib |  |