| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ttukeylem.1 |  | 
						
							| 2 |  | ttukeylem.2 |  | 
						
							| 3 |  | ttukeylem.3 |  | 
						
							| 4 |  | ttukeylem.4 |  | 
						
							| 5 |  | sseq2 |  | 
						
							| 6 |  | fveq2 |  | 
						
							| 7 | 6 | sseq2d |  | 
						
							| 8 | 5 7 | imbi12d |  | 
						
							| 9 | 8 | imbi2d |  | 
						
							| 10 |  | sseq2 |  | 
						
							| 11 |  | fveq2 |  | 
						
							| 12 | 11 | sseq2d |  | 
						
							| 13 | 10 12 | imbi12d |  | 
						
							| 14 | 13 | imbi2d |  | 
						
							| 15 |  | r19.21v |  | 
						
							| 16 |  | onsseleq |  | 
						
							| 17 | 16 | ad4ant23 |  | 
						
							| 18 |  | sseq2 |  | 
						
							| 19 |  | sseq2 |  | 
						
							| 20 | 4 | tfr1 |  | 
						
							| 21 |  | simplr |  | 
						
							| 22 |  | onss |  | 
						
							| 23 | 21 22 | syl |  | 
						
							| 24 |  | simprr |  | 
						
							| 25 |  | fnfvima |  | 
						
							| 26 | 20 23 24 25 | mp3an2i |  | 
						
							| 27 |  | elssuni |  | 
						
							| 28 | 26 27 | syl |  | 
						
							| 29 |  | n0i |  | 
						
							| 30 |  | iffalse |  | 
						
							| 31 | 24 29 30 | 3syl |  | 
						
							| 32 | 28 31 | sseqtrrd |  | 
						
							| 33 | 32 | adantr |  | 
						
							| 34 | 24 | adantr |  | 
						
							| 35 |  | elssuni |  | 
						
							| 36 | 34 35 | syl |  | 
						
							| 37 |  | sseq2 |  | 
						
							| 38 |  | fveq2 |  | 
						
							| 39 | 38 | sseq2d |  | 
						
							| 40 | 37 39 | imbi12d |  | 
						
							| 41 |  | simplrl |  | 
						
							| 42 |  | vuniex |  | 
						
							| 43 | 42 | sucid |  | 
						
							| 44 |  | eloni |  | 
						
							| 45 |  | orduniorsuc |  | 
						
							| 46 | 21 44 45 | 3syl |  | 
						
							| 47 | 46 | orcanai |  | 
						
							| 48 | 43 47 | eleqtrrid |  | 
						
							| 49 | 40 41 48 | rspcdva |  | 
						
							| 50 | 36 49 | mpd |  | 
						
							| 51 |  | ssun1 |  | 
						
							| 52 | 50 51 | sstrdi |  | 
						
							| 53 | 18 19 33 52 | ifbothda |  | 
						
							| 54 | 1 2 3 4 | ttukeylem3 |  | 
						
							| 55 | 54 | ad4ant13 |  | 
						
							| 56 | 53 55 | sseqtrrd |  | 
						
							| 57 | 56 | expr |  | 
						
							| 58 |  | fveq2 |  | 
						
							| 59 |  | eqimss |  | 
						
							| 60 | 58 59 | syl |  | 
						
							| 61 | 60 | a1i |  | 
						
							| 62 | 57 61 | jaod |  | 
						
							| 63 | 17 62 | sylbid |  | 
						
							| 64 | 63 | ex |  | 
						
							| 65 | 64 | expcom |  | 
						
							| 66 | 65 | a2d |  | 
						
							| 67 | 15 66 | biimtrid |  | 
						
							| 68 | 9 14 67 | tfis3 |  | 
						
							| 69 | 68 | expdcom |  | 
						
							| 70 | 69 | 3imp2 |  |