| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dihoml4.h |  | 
						
							| 2 |  | dihoml4.u |  | 
						
							| 3 |  | dihoml4.s |  | 
						
							| 4 |  | dihoml4.o |  | 
						
							| 5 |  | dihoml4.k |  | 
						
							| 6 |  | dihoml4.x |  | 
						
							| 7 |  | dihoml4.y |  | 
						
							| 8 |  | dihoml4.c |  | 
						
							| 9 |  | dihoml4.l |  | 
						
							| 10 |  | eqid |  | 
						
							| 11 | 10 3 | lssss |  | 
						
							| 12 | 6 11 | syl |  | 
						
							| 13 |  | eqid |  | 
						
							| 14 | 1 13 2 10 4 | dochcl |  | 
						
							| 15 | 5 12 14 | syl2anc |  | 
						
							| 16 | 1 13 4 | dochoc |  | 
						
							| 17 | 5 15 16 | syl2anc |  | 
						
							| 18 | 17 | ineq1d |  | 
						
							| 19 | 18 | fveq2d |  | 
						
							| 20 | 19 | ineq1d |  | 
						
							| 21 | 1 2 10 4 | dochssv |  | 
						
							| 22 | 5 12 21 | syl2anc |  | 
						
							| 23 | 1 13 2 10 4 | dochcl |  | 
						
							| 24 | 5 22 23 | syl2anc |  | 
						
							| 25 | 10 3 | lssss |  | 
						
							| 26 | 7 25 | syl |  | 
						
							| 27 | 1 13 2 10 4 5 26 | dochoccl |  | 
						
							| 28 | 8 27 | mpbird |  | 
						
							| 29 | 1 2 10 4 | dochss |  | 
						
							| 30 | 5 26 9 29 | syl3anc |  | 
						
							| 31 | 1 2 10 4 | dochss |  | 
						
							| 32 | 5 22 30 31 | syl3anc |  | 
						
							| 33 | 32 8 | sseqtrd |  | 
						
							| 34 | 1 13 4 5 24 28 33 | dihoml4c |  | 
						
							| 35 | 20 34 | eqtr3d |  |