| Step | Hyp | Ref | Expression | 
						
							| 1 |  | shftfval.1 |  | 
						
							| 2 | 1 | shftfval |  | 
						
							| 3 | 2 | breqd |  | 
						
							| 4 |  | eleq1 |  | 
						
							| 5 |  | oveq1 |  | 
						
							| 6 | 5 | breq1d |  | 
						
							| 7 | 4 6 | anbi12d |  | 
						
							| 8 |  | breq2 |  | 
						
							| 9 | 8 | anbi2d |  | 
						
							| 10 |  | eqid |  | 
						
							| 11 | 7 9 10 | brabg |  | 
						
							| 12 | 11 | elvd |  | 
						
							| 13 | 3 12 | sylan9bb |  | 
						
							| 14 |  | ibar |  | 
						
							| 15 | 14 | adantl |  | 
						
							| 16 | 13 15 | bitr4d |  | 
						
							| 17 | 16 | abbidv |  | 
						
							| 18 |  | imasng |  | 
						
							| 19 | 18 | adantl |  | 
						
							| 20 |  | ovex |  | 
						
							| 21 |  | imasng |  | 
						
							| 22 | 20 21 | mp1i |  | 
						
							| 23 | 17 19 22 | 3eqtr4d |  |