| Step | Hyp | Ref | Expression | 
						
							| 1 |  | wlkiswwlks2lem.f |  | 
						
							| 2 |  | wlkiswwlks2lem.e |  | 
						
							| 3 | 2 | uspgrf1oedg |  | 
						
							| 4 | 2 | rneqi |  | 
						
							| 5 |  | edgval |  | 
						
							| 6 | 4 5 | eqtr4i |  | 
						
							| 7 | 6 | a1i |  | 
						
							| 8 | 7 | f1oeq3d |  | 
						
							| 9 | 3 8 | mpbird |  | 
						
							| 10 | 9 | 3ad2ant1 |  | 
						
							| 11 | 10 | ad2antrr |  | 
						
							| 12 |  | simpr |  | 
						
							| 13 |  | fveq2 |  | 
						
							| 14 |  | fvoveq1 |  | 
						
							| 15 | 13 14 | preq12d |  | 
						
							| 16 | 15 | eleq1d |  | 
						
							| 17 | 16 | adantl |  | 
						
							| 18 | 12 17 | rspcdv |  | 
						
							| 19 | 18 | impancom |  | 
						
							| 20 | 19 | imp |  | 
						
							| 21 |  | f1ocnvdm |  | 
						
							| 22 | 11 20 21 | syl2anc |  | 
						
							| 23 | 22 1 | fmptd |  | 
						
							| 24 |  | iswrdi |  | 
						
							| 25 | 23 24 | syl |  | 
						
							| 26 | 25 | ex |  |