| Step | Hyp | Ref | Expression | 
						
							| 1 |  | hstcl |  | 
						
							| 2 |  | choccl |  | 
						
							| 3 |  | hstcl |  | 
						
							| 4 | 2 3 | sylan2 |  | 
						
							| 5 |  | his7 |  | 
						
							| 6 | 1 1 4 5 | syl3anc |  | 
						
							| 7 |  | normsq |  | 
						
							| 8 | 1 7 | syl |  | 
						
							| 9 | 8 | eqcomd |  | 
						
							| 10 |  | ococ |  | 
						
							| 11 |  | eqimss2 |  | 
						
							| 12 | 10 11 | syl |  | 
						
							| 13 | 2 12 | jca |  | 
						
							| 14 | 13 | adantl |  | 
						
							| 15 |  | hstorth |  | 
						
							| 16 | 14 15 | mpdan |  | 
						
							| 17 | 9 16 | oveq12d |  | 
						
							| 18 |  | normcl |  | 
						
							| 19 | 1 18 | syl |  | 
						
							| 20 | 19 | resqcld |  | 
						
							| 21 | 20 | recnd |  | 
						
							| 22 | 21 | addridd |  | 
						
							| 23 | 6 17 22 | 3eqtrrd |  | 
						
							| 24 |  | hstoc |  | 
						
							| 25 | 24 | oveq2d |  | 
						
							| 26 | 23 25 | eqtrd |  | 
						
							| 27 |  | id |  | 
						
							| 28 | 26 27 | sylan9eq |  | 
						
							| 29 | 28 | 3impa |  | 
						
							| 30 | 19 | recnd |  | 
						
							| 31 |  | sqeq0 |  | 
						
							| 32 | 30 31 | syl |  | 
						
							| 33 | 32 | 3adant3 |  | 
						
							| 34 | 29 33 | mpbid |  | 
						
							| 35 |  | hst0h |  | 
						
							| 36 | 35 | 3adant3 |  | 
						
							| 37 | 34 36 | mpbid |  |