| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 4at.l |  | 
						
							| 2 |  | 4at.j |  | 
						
							| 3 |  | 4at.a |  | 
						
							| 4 |  | simprr |  | 
						
							| 5 |  | simprl |  | 
						
							| 6 |  | simpl1 |  | 
						
							| 7 |  | simpl21 |  | 
						
							| 8 |  | simpl23 |  | 
						
							| 9 |  | simpl31 |  | 
						
							| 10 |  | simpl32 |  | 
						
							| 11 | 1 2 3 | 4atlem10a |  | 
						
							| 12 | 6 7 8 9 10 11 | syl131anc |  | 
						
							| 13 | 5 12 | mpbid |  | 
						
							| 14 | 4 13 | breqtrrd |  | 
						
							| 15 |  | simpl22 |  | 
						
							| 16 |  | simpl33 |  | 
						
							| 17 | 1 2 3 | 4atlem9 |  | 
						
							| 18 | 6 7 15 9 16 17 | syl131anc |  | 
						
							| 19 | 14 18 | mpbid |  | 
						
							| 20 | 19 13 | eqtrd |  |