| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ltso |  | 
						
							| 2 |  | eqid |  | 
						
							| 3 |  | f1oiso |  | 
						
							| 4 | 2 3 | mpan2 |  | 
						
							| 5 |  | isoso |  | 
						
							| 6 |  | soinxp |  | 
						
							| 7 | 5 6 | bitrdi |  | 
						
							| 8 | 4 7 | syl |  | 
						
							| 9 | 1 8 | mpbii |  | 
						
							| 10 |  | cnex |  | 
						
							| 11 | 10 10 | xpex |  | 
						
							| 12 | 11 | inex2 |  | 
						
							| 13 |  | soeq1 |  | 
						
							| 14 | 12 13 | spcev |  | 
						
							| 15 | 9 14 | syl |  | 
						
							| 16 |  | rpnnen |  | 
						
							| 17 |  | cpnnen |  | 
						
							| 18 | 16 17 | entr4i |  | 
						
							| 19 |  | bren |  | 
						
							| 20 | 18 19 | mpbi |  | 
						
							| 21 | 15 20 | exlimiiv |  |