| Step | Hyp | Ref | Expression | 
						
							| 1 |  | atbtwn.b |  | 
						
							| 2 |  | atbtwn.l |  | 
						
							| 3 |  | atbtwn.j |  | 
						
							| 4 |  | atbtwn.a |  | 
						
							| 5 |  | simpl33 |  | 
						
							| 6 |  | simpr |  | 
						
							| 7 |  | simpl11 |  | 
						
							| 8 | 7 | hllatd |  | 
						
							| 9 |  | simpl2l |  | 
						
							| 10 | 1 4 | atbase |  | 
						
							| 11 | 9 10 | syl |  | 
						
							| 12 |  | simpl1 |  | 
						
							| 13 | 1 3 4 | hlatjcl |  | 
						
							| 14 | 12 13 | syl |  | 
						
							| 15 |  | simpl2r |  | 
						
							| 16 |  | eqid |  | 
						
							| 17 | 1 2 16 | latlem12 |  | 
						
							| 18 | 8 11 14 15 17 | syl13anc |  | 
						
							| 19 | 5 6 18 | mpbi2and |  | 
						
							| 20 |  | simpl12 |  | 
						
							| 21 |  | simpl13 |  | 
						
							| 22 |  | simpl31 |  | 
						
							| 23 |  | simpl32 |  | 
						
							| 24 | 1 2 3 16 4 | 2atjm |  | 
						
							| 25 | 7 20 21 15 22 23 24 | syl132anc |  | 
						
							| 26 | 19 25 | breqtrd |  | 
						
							| 27 |  | hlatl |  | 
						
							| 28 | 7 27 | syl |  | 
						
							| 29 | 2 4 | atcmp |  | 
						
							| 30 | 28 9 20 29 | syl3anc |  | 
						
							| 31 | 26 30 | mpbid |  | 
						
							| 32 | 31 | ex |  | 
						
							| 33 | 32 | necon3ad |  | 
						
							| 34 |  | simp31 |  | 
						
							| 35 |  | nbrne2 |  | 
						
							| 36 | 35 | necomd |  | 
						
							| 37 | 36 | ex |  | 
						
							| 38 | 34 37 | syl |  | 
						
							| 39 | 33 38 | impbid |  |