Metamath Proof Explorer
		
		
		
		Description:  Bound-variable hypothesis builder for binary relation.  (Contributed by NM, 1-Sep-1999)  (Revised by Mario Carneiro, 14-Oct-2016)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | nfbr.1 | |- F/_ x A | 
					
						|  |  | nfbr.2 | |- F/_ x R | 
					
						|  |  | nfbr.3 | |- F/_ x B | 
				
					|  | Assertion | nfbr | |- F/ x A R B | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nfbr.1 |  |-  F/_ x A | 
						
							| 2 |  | nfbr.2 |  |-  F/_ x R | 
						
							| 3 |  | nfbr.3 |  |-  F/_ x B | 
						
							| 4 | 1 | a1i |  |-  ( T. -> F/_ x A ) | 
						
							| 5 | 2 | a1i |  |-  ( T. -> F/_ x R ) | 
						
							| 6 | 3 | a1i |  |-  ( T. -> F/_ x B ) | 
						
							| 7 | 4 5 6 | nfbrd |  |-  ( T. -> F/ x A R B ) | 
						
							| 8 | 7 | mptru |  |-  F/ x A R B |