Proof of Theorem istoset2
| Step | Hyp | Ref
| Expression |
| 1 | | tosdir 10358 |
. . . . 5
Toset Dir |
| 2 | 1 | sseli 2617 |
. . . 4

Toset Dir |
| 3 | | dirdm 10354 |
. . . 4
 Dir
    |
| 4 | 2, 3 | syl 12 |
. . 3

Toset     |
| 5 | | istoset2.1 |
. . . 4
 |
| 6 | | eqtr 1904 |
. . . . 5
         |
| 7 | | id 73 |
. . . . . . . 8
  
    |
| 8 | | raleq 2266 |
. . . . . . . 8
  
 
                   |
| 9 | 7, 8 | raleqbidv 2274 |
. . . . . . 7
  
 

                       |
| 10 | 9 | anbi2d 678 |
. . . . . 6
  
  Poset 

        Poset                   |
| 11 | | eqid 1884 |
. . . . . . . 8
     |
| 12 | 11 | istoset 10209 |
. . . . . . 7

Toset  Toset  Poset                   |
| 13 | 12 | ibi 652 |
. . . . . 6

Toset  Poset
    
            |
| 14 | 10, 13 | syl5bir 227 |
. . . . 5
  
 Toset  Poset             |
| 15 | 6, 14 | syl 12 |
. . . 4
      Toset  Poset             |
| 16 | 5, 15 | mpan 759 |
. . 3

 

Toset  Poset


          |
| 17 | 4, 16 | mpcom 60 |
. 2

Toset  Poset


         |
| 18 | | posispre 14582 |
. . . . 5

Poset Preset  |
| 19 | | preodom2 14567 |
. . . . 5

Preset     |
| 20 | | biidd 188 |
. . . . . . . . . . 11
  
                |
| 21 | 7, 20 | raleqbidv 2274 |
. . . . . . . . . 10
  
 
                   |
| 22 | 7, 21 | raleqbidv 2274 |
. . . . . . . . 9
  
 

                       |
| 23 | 22 | imbi1d 675 |
. . . . . . . 8
  
          Toset      
         Toset    |
| 24 | 11 | istoset 10209 |
. . . . . . . . . . 11

Poset  Toset  Poset                   |
| 25 | 24 | biimprd 171 |
. . . . . . . . . 10

Poset   Poset 
              Toset   |
| 26 | 25 | exp3a 405 |
. . . . . . . . 9

Poset  Poset
 
             Toset    |
| 27 | 26 | pm2.43i 78 |
. . . . . . . 8

Poset                Toset   |
| 28 | 23, 27 | syl5bir 227 |
. . . . . . 7
  
 Poset  

      Toset    |
| 29 | 6, 28 | syl 12 |
. . . . . 6
      Poset          Toset    |
| 30 | 5, 29 | mpan 759 |
. . . . 5

 

Poset   
      Toset    |
| 31 | 18, 19, 30 | 3syl 24 |
. . . 4

Poset  Poset
 

      Toset    |
| 32 | 31 | pm2.43i 78 |
. . 3

Poset   
      Toset   |
| 33 | 32 | imp 377 |
. 2
  Poset          Toset  |
| 34 | 17, 33 | impbii 174 |
1

Toset  Poset            |