Metamath Proof Explorer
		
		
		
		Description:  Bound-variable hypothesis builder for well-orderings.  (Contributed by Stefan O'Rear, 20-Jan-2015)  (Revised by Mario Carneiro, 14-Oct-2016)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | nffr.r | ⊢ Ⅎ 𝑥 𝑅 | 
					
						|  |  | nffr.a | ⊢ Ⅎ 𝑥 𝐴 | 
				
					|  | Assertion | nfwe | ⊢  Ⅎ 𝑥 𝑅  We  𝐴 | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nffr.r | ⊢ Ⅎ 𝑥 𝑅 | 
						
							| 2 |  | nffr.a | ⊢ Ⅎ 𝑥 𝐴 | 
						
							| 3 |  | df-we | ⊢ ( 𝑅  We  𝐴  ↔  ( 𝑅  Fr  𝐴  ∧  𝑅  Or  𝐴 ) ) | 
						
							| 4 | 1 2 | nffr | ⊢ Ⅎ 𝑥 𝑅  Fr  𝐴 | 
						
							| 5 | 1 2 | nfso | ⊢ Ⅎ 𝑥 𝑅  Or  𝐴 | 
						
							| 6 | 4 5 | nfan | ⊢ Ⅎ 𝑥 ( 𝑅  Fr  𝐴  ∧  𝑅  Or  𝐴 ) | 
						
							| 7 | 3 6 | nfxfr | ⊢ Ⅎ 𝑥 𝑅  We  𝐴 |