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 | 
						bnj1351.1 | 
						   | 
					
				
					 | 
					Assertion | 
					bnj1351 | 
					   | 
				
			
		
		
			
				Proof
				
					
						| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj1351.1 | 
							   | 
						
						
							| 2 | 
							
								
							 | 
							ax-5 | 
							   | 
						
						
							| 3 | 
							
								1 2
							 | 
							hban | 
							   |