| Step | Hyp | Ref | Expression | 
						
							| 1 |  | difss |  | 
						
							| 2 |  | dmss |  | 
						
							| 3 | 1 2 | ax-mp |  | 
						
							| 4 |  | dmcoss |  | 
						
							| 5 | 3 4 | sstri |  | 
						
							| 6 |  | f1ocnv |  | 
						
							| 7 | 6 | adantl |  | 
						
							| 8 |  | f1odm |  | 
						
							| 9 | 7 8 | syl |  | 
						
							| 10 | 5 9 | sseqtrid |  | 
						
							| 11 | 10 | sselda |  | 
						
							| 12 |  | imassrn |  | 
						
							| 13 |  | f1of |  | 
						
							| 14 | 13 | adantl |  | 
						
							| 15 | 14 | frnd |  | 
						
							| 16 | 12 15 | sstrid |  | 
						
							| 17 | 16 | sselda |  | 
						
							| 18 |  | simpl |  | 
						
							| 19 |  | fco |  | 
						
							| 20 | 14 18 19 | syl2anc |  | 
						
							| 21 |  | f1of |  | 
						
							| 22 | 7 21 | syl |  | 
						
							| 23 |  | fco |  | 
						
							| 24 | 20 22 23 | syl2anc |  | 
						
							| 25 | 24 | ffnd |  | 
						
							| 26 |  | fnelnfp |  | 
						
							| 27 | 25 26 | sylan |  | 
						
							| 28 |  | f1ofn |  | 
						
							| 29 | 7 28 | syl |  | 
						
							| 30 |  | fvco2 |  | 
						
							| 31 | 29 30 | sylan |  | 
						
							| 32 |  | ffn |  | 
						
							| 33 | 32 | ad2antrr |  | 
						
							| 34 |  | ffvelcdm |  | 
						
							| 35 | 22 34 | sylan |  | 
						
							| 36 |  | fvco2 |  | 
						
							| 37 | 33 35 36 | syl2anc |  | 
						
							| 38 | 31 37 | eqtrd |  | 
						
							| 39 | 38 | eqeq1d |  | 
						
							| 40 |  | simplr |  | 
						
							| 41 |  | simpll |  | 
						
							| 42 |  | ffvelcdm |  | 
						
							| 43 | 41 35 42 | syl2anc |  | 
						
							| 44 |  | simpr |  | 
						
							| 45 |  | f1ocnvfvb |  | 
						
							| 46 | 40 43 44 45 | syl3anc |  | 
						
							| 47 | 39 46 | bitrd |  | 
						
							| 48 | 47 | necon3bid |  | 
						
							| 49 |  | necom |  | 
						
							| 50 |  | f1of1 |  | 
						
							| 51 | 50 | ad2antlr |  | 
						
							| 52 |  | difss |  | 
						
							| 53 |  | dmss |  | 
						
							| 54 | 52 53 | ax-mp |  | 
						
							| 55 |  | fdm |  | 
						
							| 56 | 54 55 | sseqtrid |  | 
						
							| 57 | 56 | ad2antrr |  | 
						
							| 58 |  | f1elima |  | 
						
							| 59 | 51 35 57 58 | syl3anc |  | 
						
							| 60 |  | f1ocnvfv2 |  | 
						
							| 61 | 60 | adantll |  | 
						
							| 62 | 61 | eleq1d |  | 
						
							| 63 |  | fnelnfp |  | 
						
							| 64 | 33 35 63 | syl2anc |  | 
						
							| 65 | 59 62 64 | 3bitr3rd |  | 
						
							| 66 | 49 65 | bitrid |  | 
						
							| 67 | 27 48 66 | 3bitrd |  | 
						
							| 68 | 11 17 67 | eqrdav |  |