Metamath Proof Explorer
		
		
		
		Description:  Lemma 2 for 2wlkd .  (Contributed by AV, 14-Feb-2021)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | 2wlkd.p |  | 
					
						|  |  | 2wlkd.f |  | 
				
					|  | Assertion | 2wlkdlem2 |  | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2wlkd.p |  | 
						
							| 2 |  | 2wlkd.f |  | 
						
							| 3 | 2 | fveq2i |  | 
						
							| 4 |  | s2len |  | 
						
							| 5 | 3 4 | eqtri |  | 
						
							| 6 | 5 | oveq2i |  | 
						
							| 7 |  | fzo0to2pr |  | 
						
							| 8 | 6 7 | eqtri |  |