| Step | Hyp | Ref | Expression | 
						
							| 1 |  | iccshift.1 |  | 
						
							| 2 |  | iccshift.2 |  | 
						
							| 3 |  | iccshift.3 |  | 
						
							| 4 |  | eqeq1 |  | 
						
							| 5 | 4 | rexbidv |  | 
						
							| 6 | 5 | elrab |  | 
						
							| 7 |  | simprr |  | 
						
							| 8 |  | nfv |  | 
						
							| 9 |  | nfv |  | 
						
							| 10 |  | nfre1 |  | 
						
							| 11 | 9 10 | nfan |  | 
						
							| 12 | 8 11 | nfan |  | 
						
							| 13 |  | nfv |  | 
						
							| 14 |  | simp3 |  | 
						
							| 15 | 1 2 | iccssred |  | 
						
							| 16 | 15 | sselda |  | 
						
							| 17 | 3 | adantr |  | 
						
							| 18 | 16 17 | readdcld |  | 
						
							| 19 | 1 | adantr |  | 
						
							| 20 |  | simpr |  | 
						
							| 21 | 2 | adantr |  | 
						
							| 22 |  | elicc2 |  | 
						
							| 23 | 19 21 22 | syl2anc |  | 
						
							| 24 | 20 23 | mpbid |  | 
						
							| 25 | 24 | simp2d |  | 
						
							| 26 | 19 16 17 25 | leadd1dd |  | 
						
							| 27 | 24 | simp3d |  | 
						
							| 28 | 16 21 17 27 | leadd1dd |  | 
						
							| 29 | 18 26 28 | 3jca |  | 
						
							| 30 | 29 | 3adant3 |  | 
						
							| 31 | 1 3 | readdcld |  | 
						
							| 32 | 31 | 3ad2ant1 |  | 
						
							| 33 | 2 3 | readdcld |  | 
						
							| 34 | 33 | 3ad2ant1 |  | 
						
							| 35 |  | elicc2 |  | 
						
							| 36 | 32 34 35 | syl2anc |  | 
						
							| 37 | 30 36 | mpbird |  | 
						
							| 38 | 14 37 | eqeltrd |  | 
						
							| 39 | 38 | 3exp |  | 
						
							| 40 | 39 | adantr |  | 
						
							| 41 | 12 13 40 | rexlimd |  | 
						
							| 42 | 7 41 | mpd |  | 
						
							| 43 | 6 42 | sylan2b |  | 
						
							| 44 | 31 | adantr |  | 
						
							| 45 | 33 | adantr |  | 
						
							| 46 |  | simpr |  | 
						
							| 47 |  | eliccre |  | 
						
							| 48 | 44 45 46 47 | syl3anc |  | 
						
							| 49 | 48 | recnd |  | 
						
							| 50 | 1 | adantr |  | 
						
							| 51 | 2 | adantr |  | 
						
							| 52 | 3 | adantr |  | 
						
							| 53 | 48 52 | resubcld |  | 
						
							| 54 | 1 | recnd |  | 
						
							| 55 | 3 | recnd |  | 
						
							| 56 | 54 55 | pncand |  | 
						
							| 57 | 56 | eqcomd |  | 
						
							| 58 | 57 | adantr |  | 
						
							| 59 |  | elicc2 |  | 
						
							| 60 | 44 45 59 | syl2anc |  | 
						
							| 61 | 46 60 | mpbid |  | 
						
							| 62 | 61 | simp2d |  | 
						
							| 63 | 44 48 52 62 | lesub1dd |  | 
						
							| 64 | 58 63 | eqbrtrd |  | 
						
							| 65 | 61 | simp3d |  | 
						
							| 66 | 48 45 52 65 | lesub1dd |  | 
						
							| 67 | 2 | recnd |  | 
						
							| 68 | 67 55 | pncand |  | 
						
							| 69 | 68 | adantr |  | 
						
							| 70 | 66 69 | breqtrd |  | 
						
							| 71 | 50 51 53 64 70 | eliccd |  | 
						
							| 72 | 55 | adantr |  | 
						
							| 73 | 49 72 | npcand |  | 
						
							| 74 | 73 | eqcomd |  | 
						
							| 75 |  | oveq1 |  | 
						
							| 76 | 75 | rspceeqv |  | 
						
							| 77 | 71 74 76 | syl2anc |  | 
						
							| 78 | 49 77 6 | sylanbrc |  | 
						
							| 79 | 43 78 | impbida |  | 
						
							| 80 | 79 | eqrdv |  | 
						
							| 81 | 80 | eqcomd |  |