| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdslle1.1 |  | 
						
							| 2 |  | mdslle1.2 |  | 
						
							| 3 |  | mdslle1.3 |  | 
						
							| 4 |  | mdslle1.4 |  | 
						
							| 5 |  | ssrin |  | 
						
							| 6 | 3 2 | chincli |  | 
						
							| 7 | 4 2 | chincli |  | 
						
							| 8 | 6 7 1 | chlej1i |  | 
						
							| 9 |  | id |  | 
						
							| 10 |  | ssin |  | 
						
							| 11 | 10 | bicomi |  | 
						
							| 12 | 11 | simplbi |  | 
						
							| 13 | 1 2 | chjcli |  | 
						
							| 14 | 3 4 13 | chlubi |  | 
						
							| 15 | 14 | bicomi |  | 
						
							| 16 | 15 | simplbi |  | 
						
							| 17 | 1 2 3 | 3pm3.2i |  | 
						
							| 18 |  | dmdsl3 |  | 
						
							| 19 | 17 18 | mpan |  | 
						
							| 20 | 9 12 16 19 | syl3an |  | 
						
							| 21 | 11 | simprbi |  | 
						
							| 22 | 15 | simprbi |  | 
						
							| 23 | 1 2 4 | 3pm3.2i |  | 
						
							| 24 |  | dmdsl3 |  | 
						
							| 25 | 23 24 | mpan |  | 
						
							| 26 | 9 21 22 25 | syl3an |  | 
						
							| 27 | 20 26 | sseq12d |  | 
						
							| 28 | 8 27 | imbitrid |  | 
						
							| 29 | 5 28 | impbid2 |  |