| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-3an |  | 
						
							| 2 | 1 | biimpri |  | 
						
							| 3 | 2 | 3adant2 |  | 
						
							| 4 |  | ssfzo12 |  | 
						
							| 5 | 3 4 | syl |  | 
						
							| 6 |  | elfzo2 |  | 
						
							| 7 |  | eluz2 |  | 
						
							| 8 |  | simprrl |  | 
						
							| 9 | 8 | adantr |  | 
						
							| 10 |  | simpll |  | 
						
							| 11 |  | zre |  | 
						
							| 12 | 11 | adantr |  | 
						
							| 13 | 12 | adantl |  | 
						
							| 14 |  | zre |  | 
						
							| 15 | 14 | adantr |  | 
						
							| 16 | 15 | adantr |  | 
						
							| 17 |  | zre |  | 
						
							| 18 | 17 | adantr |  | 
						
							| 19 |  | letr |  | 
						
							| 20 | 13 16 18 19 | syl2an23an |  | 
						
							| 21 | 20 | imp |  | 
						
							| 22 | 9 10 21 | 3jca |  | 
						
							| 23 | 22 | exp31 |  | 
						
							| 24 | 23 | com23 |  | 
						
							| 25 | 24 | expdimp |  | 
						
							| 26 | 25 | impancom |  | 
						
							| 27 | 26 | com13 |  | 
						
							| 28 | 27 | 3adant3 |  | 
						
							| 29 | 28 | com12 |  | 
						
							| 30 | 29 | adantr |  | 
						
							| 31 | 30 | impcom |  | 
						
							| 32 | 31 | com12 |  | 
						
							| 33 | 32 | adantr |  | 
						
							| 34 | 33 | imp |  | 
						
							| 35 |  | eluz2 |  | 
						
							| 36 | 34 35 | sylibr |  | 
						
							| 37 |  | simpl2r |  | 
						
							| 38 | 37 | adantl |  | 
						
							| 39 | 17 | adantl |  | 
						
							| 40 |  | zre |  | 
						
							| 41 | 40 | ad3antlr |  | 
						
							| 42 |  | zre |  | 
						
							| 43 | 42 | adantl |  | 
						
							| 44 | 43 | adantl |  | 
						
							| 45 | 44 | adantr |  | 
						
							| 46 |  | ltletr |  | 
						
							| 47 | 39 41 45 46 | syl3anc |  | 
						
							| 48 | 47 | ex |  | 
						
							| 49 | 48 | com23 |  | 
						
							| 50 | 49 | 3adant3 |  | 
						
							| 51 | 50 | expcomd |  | 
						
							| 52 | 51 | adantld |  | 
						
							| 53 | 52 | imp |  | 
						
							| 54 | 53 | com13 |  | 
						
							| 55 | 54 | adantr |  | 
						
							| 56 | 55 | imp |  | 
						
							| 57 | 56 | imp |  | 
						
							| 58 |  | elfzo2 |  | 
						
							| 59 | 36 38 57 58 | syl3anbrc |  | 
						
							| 60 | 59 | exp31 |  | 
						
							| 61 | 60 | 3adant1 |  | 
						
							| 62 | 7 61 | sylbi |  | 
						
							| 63 | 62 | imp |  | 
						
							| 64 | 63 | 3adant2 |  | 
						
							| 65 | 6 64 | sylbi |  | 
						
							| 66 | 65 | com12 |  | 
						
							| 67 | 66 | ssrdv |  | 
						
							| 68 | 67 | ex |  | 
						
							| 69 | 5 68 | impbid |  |