Metamath Proof Explorer
		
		
		
		Description:  The first argument of a binary relation exists.  (An artifact of our
       ordered pair definition.)  (Contributed by NM, 4-Jun-1998)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypothesis | brrelexi.1 |  | 
				
					|  | Assertion | brrelex1i |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | brrelexi.1 |  | 
						
							| 2 |  | brrelex1 |  | 
						
							| 3 | 1 2 | mpan |  |