| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dihord.b |  | 
						
							| 2 |  | dihord.l |  | 
						
							| 3 |  | dihord.h |  | 
						
							| 4 |  | dihord.i |  | 
						
							| 5 |  | simpl1 |  | 
						
							| 6 |  | simpl2 |  | 
						
							| 7 |  | simprl |  | 
						
							| 8 |  | simpl3 |  | 
						
							| 9 |  | simprr |  | 
						
							| 10 | 1 2 3 4 | dihord3 |  | 
						
							| 11 | 5 6 7 8 9 10 | syl122anc |  | 
						
							| 12 |  | simpl1 |  | 
						
							| 13 |  | simpl2 |  | 
						
							| 14 |  | simprl |  | 
						
							| 15 |  | simpl3 |  | 
						
							| 16 |  | simprr |  | 
						
							| 17 | 1 2 3 4 | dihord5a |  | 
						
							| 18 | 1 2 3 4 | dihord5b |  | 
						
							| 19 | 17 18 | impbida |  | 
						
							| 20 | 12 13 14 15 16 19 | syl122anc |  | 
						
							| 21 |  | simpl1 |  | 
						
							| 22 |  | simpl2 |  | 
						
							| 23 |  | simprl |  | 
						
							| 24 |  | simpl3 |  | 
						
							| 25 |  | simprr |  | 
						
							| 26 | 1 2 3 4 | dihord6a |  | 
						
							| 27 | 1 2 3 4 | dihord6b |  | 
						
							| 28 | 26 27 | impbida |  | 
						
							| 29 | 21 22 23 24 25 28 | syl122anc |  | 
						
							| 30 |  | simpl1 |  | 
						
							| 31 |  | simpl2 |  | 
						
							| 32 |  | simprl |  | 
						
							| 33 |  | simpl3 |  | 
						
							| 34 |  | simprr |  | 
						
							| 35 | 1 2 3 4 | dihord4 |  | 
						
							| 36 | 30 31 32 33 34 35 | syl122anc |  | 
						
							| 37 | 11 20 29 36 | 4casesdan |  |