| Step | Hyp | Ref | Expression | 
						
							| 1 |  | xpsfrnel |  | 
						
							| 2 |  | fnpr2ob |  | 
						
							| 3 | 2 | biimpri |  | 
						
							| 4 | 3 | 3ad2ant1 |  | 
						
							| 5 |  | elex |  | 
						
							| 6 |  | elex |  | 
						
							| 7 | 5 6 | anim12i |  | 
						
							| 8 |  | 3anass |  | 
						
							| 9 |  | fnpr2o |  | 
						
							| 10 | 9 | biantrurd |  | 
						
							| 11 |  | fvpr0o |  | 
						
							| 12 | 11 | eleq1d |  | 
						
							| 13 |  | fvpr1o |  | 
						
							| 14 | 13 | eleq1d |  | 
						
							| 15 | 12 14 | bi2anan9 |  | 
						
							| 16 | 10 15 | bitr3d |  | 
						
							| 17 | 8 16 | bitrid |  | 
						
							| 18 | 4 7 17 | pm5.21nii |  | 
						
							| 19 | 1 18 | bitri |  |