| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elex |  | 
						
							| 2 |  | elex |  | 
						
							| 3 | 1 2 | anim12i |  | 
						
							| 4 |  | elex |  | 
						
							| 5 |  | elex |  | 
						
							| 6 | 4 5 | anim12i |  | 
						
							| 7 |  | neeq1 |  | 
						
							| 8 |  | opeq1 |  | 
						
							| 9 | 8 | preq1d |  | 
						
							| 10 |  | preq1 |  | 
						
							| 11 | 9 10 | feq12d |  | 
						
							| 12 | 7 11 | imbi12d |  | 
						
							| 13 |  | neeq2 |  | 
						
							| 14 |  | opeq1 |  | 
						
							| 15 | 14 | preq2d |  | 
						
							| 16 |  | preq2 |  | 
						
							| 17 | 15 16 | feq12d |  | 
						
							| 18 | 13 17 | imbi12d |  | 
						
							| 19 |  | opeq2 |  | 
						
							| 20 | 19 | preq1d |  | 
						
							| 21 |  | eqidd |  | 
						
							| 22 |  | preq1 |  | 
						
							| 23 | 20 21 22 | feq123d |  | 
						
							| 24 | 23 | imbi2d |  | 
						
							| 25 |  | opeq2 |  | 
						
							| 26 | 25 | preq2d |  | 
						
							| 27 |  | eqidd |  | 
						
							| 28 |  | preq2 |  | 
						
							| 29 | 26 27 28 | feq123d |  | 
						
							| 30 | 29 | imbi2d |  | 
						
							| 31 |  | 0ex |  | 
						
							| 32 | 31 | elimel |  | 
						
							| 33 | 31 | elimel |  | 
						
							| 34 | 31 | elimel |  | 
						
							| 35 | 31 | elimel |  | 
						
							| 36 | 32 33 34 35 | fpr |  | 
						
							| 37 | 12 18 24 30 36 | dedth4h |  | 
						
							| 38 | 3 6 37 | syl2an |  | 
						
							| 39 | 38 | 3impia |  |