| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dipdir.1 |  | 
						
							| 2 |  | dipdir.2 |  | 
						
							| 3 |  | dipdir.7 |  | 
						
							| 4 |  | fveq2 |  | 
						
							| 5 | 1 4 | eqtrid |  | 
						
							| 6 | 5 | eleq2d |  | 
						
							| 7 | 5 | eleq2d |  | 
						
							| 8 | 5 | eleq2d |  | 
						
							| 9 | 6 7 8 | 3anbi123d |  | 
						
							| 10 |  | fveq2 |  | 
						
							| 11 | 2 10 | eqtrid |  | 
						
							| 12 | 11 | oveqd |  | 
						
							| 13 | 12 | oveq1d |  | 
						
							| 14 |  | fveq2 |  | 
						
							| 15 | 3 14 | eqtrid |  | 
						
							| 16 | 15 | oveqd |  | 
						
							| 17 | 13 16 | eqtrd |  | 
						
							| 18 | 15 | oveqd |  | 
						
							| 19 | 15 | oveqd |  | 
						
							| 20 | 18 19 | oveq12d |  | 
						
							| 21 | 17 20 | eqeq12d |  | 
						
							| 22 | 9 21 | imbi12d |  | 
						
							| 23 |  | eqid |  | 
						
							| 24 |  | eqid |  | 
						
							| 25 |  | eqid |  | 
						
							| 26 |  | eqid |  | 
						
							| 27 |  | elimphu |  | 
						
							| 28 | 23 24 25 26 27 | ipdiri |  | 
						
							| 29 | 22 28 | dedth |  | 
						
							| 30 | 29 | imp |  |