| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eqid |  | 
						
							| 2 |  | eqid |  | 
						
							| 3 | 1 2 | upgrf |  | 
						
							| 4 |  | fvex |  | 
						
							| 5 |  | fvex |  | 
						
							| 6 | 4 5 | pm3.2i |  | 
						
							| 7 |  | opex |  | 
						
							| 8 |  | eqid |  | 
						
							| 9 |  | eqid |  | 
						
							| 10 | 8 9 | isupgr |  | 
						
							| 11 | 7 10 | mp1i |  | 
						
							| 12 |  | opiedgfv |  | 
						
							| 13 | 12 | dmeqd |  | 
						
							| 14 |  | opvtxfv |  | 
						
							| 15 | 14 | pweqd |  | 
						
							| 16 | 15 | difeq1d |  | 
						
							| 17 | 16 | rabeqdv |  | 
						
							| 18 | 12 13 17 | feq123d |  | 
						
							| 19 | 11 18 | bitrd |  | 
						
							| 20 | 6 19 | mp1i |  | 
						
							| 21 | 3 20 | mpbird |  |