| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elfzoel2 |  | 
						
							| 2 |  | elfzoel1 |  | 
						
							| 3 | 1 2 | zsubcld |  | 
						
							| 4 |  | elfzoelz |  | 
						
							| 5 |  | elfzoelz |  | 
						
							| 6 |  | zsubcl |  | 
						
							| 7 | 4 5 6 | syl2an |  | 
						
							| 8 |  | dvdsabsb |  | 
						
							| 9 | 3 7 8 | syl2an2 |  | 
						
							| 10 |  | fzomaxdif |  | 
						
							| 11 |  | fzo0dvdseq |  | 
						
							| 12 | 10 11 | syl |  | 
						
							| 13 | 9 12 | bitrd |  | 
						
							| 14 | 4 | zcnd |  | 
						
							| 15 | 5 | zcnd |  | 
						
							| 16 |  | subcl |  | 
						
							| 17 | 14 15 16 | syl2an |  | 
						
							| 18 | 17 | abs00ad |  | 
						
							| 19 |  | subeq0 |  | 
						
							| 20 | 14 15 19 | syl2an |  | 
						
							| 21 | 18 20 | bitrd |  | 
						
							| 22 | 13 21 | bitrd |  |