| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2wlkd.p |  | 
						
							| 2 |  | 2wlkd.f |  | 
						
							| 3 |  | 2wlkd.s |  | 
						
							| 4 |  | 2wlkd.n |  | 
						
							| 5 | 1 2 3 | 2wlkdlem3 |  | 
						
							| 6 |  | simp1 |  | 
						
							| 7 |  | simp2 |  | 
						
							| 8 | 6 7 | neeq12d |  | 
						
							| 9 |  | simp3 |  | 
						
							| 10 | 7 9 | neeq12d |  | 
						
							| 11 | 8 10 | anbi12d |  | 
						
							| 12 | 11 | bicomd |  | 
						
							| 13 | 5 12 | syl |  | 
						
							| 14 | 4 13 | mpbid |  | 
						
							| 15 | 1 2 | 2wlkdlem2 |  | 
						
							| 16 | 15 | raleqi |  | 
						
							| 17 |  | c0ex |  | 
						
							| 18 |  | 1ex |  | 
						
							| 19 |  | fveq2 |  | 
						
							| 20 |  | fv0p1e1 |  | 
						
							| 21 | 19 20 | neeq12d |  | 
						
							| 22 |  | fveq2 |  | 
						
							| 23 |  | oveq1 |  | 
						
							| 24 |  | 1p1e2 |  | 
						
							| 25 | 23 24 | eqtrdi |  | 
						
							| 26 | 25 | fveq2d |  | 
						
							| 27 | 22 26 | neeq12d |  | 
						
							| 28 | 17 18 21 27 | ralpr |  | 
						
							| 29 | 16 28 | bitri |  | 
						
							| 30 | 14 29 | sylibr |  |