| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cnex |  | 
						
							| 2 |  | reex |  | 
						
							| 3 |  | elpm2r |  | 
						
							| 4 | 1 2 3 | mpanl12 |  | 
						
							| 5 |  | elo1 |  | 
						
							| 6 | 5 | baib |  | 
						
							| 7 | 4 6 | syl |  | 
						
							| 8 |  | elin |  | 
						
							| 9 |  | fdm |  | 
						
							| 10 | 9 | ad3antrrr |  | 
						
							| 11 | 10 | eleq2d |  | 
						
							| 12 | 11 | anbi1d |  | 
						
							| 13 |  | simpllr |  | 
						
							| 14 | 13 | sselda |  | 
						
							| 15 |  | simpllr |  | 
						
							| 16 |  | elicopnf |  | 
						
							| 17 | 15 16 | syl |  | 
						
							| 18 | 14 17 | mpbirand |  | 
						
							| 19 | 18 | pm5.32da |  | 
						
							| 20 | 12 19 | bitrd |  | 
						
							| 21 | 8 20 | bitrid |  | 
						
							| 22 | 21 | imbi1d |  | 
						
							| 23 |  | impexp |  | 
						
							| 24 | 22 23 | bitrdi |  | 
						
							| 25 | 24 | ralbidv2 |  | 
						
							| 26 | 25 | rexbidva |  | 
						
							| 27 | 26 | rexbidva |  | 
						
							| 28 | 7 27 | bitrd |  |