Proof of Theorem stoig
| Step | Hyp | Ref
| Expression |
| 1 | | opeq2 3159 |
. . . . 5
    Top         
      Top
  
       |
| 2 | 1 | fveq2d 4685 |
. . . 4
    Top        subSp     subSp      Top            |
| 3 | 2 | opeq2d 3165 |
. . 3
    Top         
subSp  
     subSp      Top             |
| 4 | 3 | eleq1d 1963 |
. 2
    Top           subSp      TopSp   subSp      Top          
TopSp  |
| 5 | | id 73 |
. . . 4
    Top     
   Top        |
| 6 | | opeq1 3158 |
. . . . 5
    Top     
     Top             Top          Top           |
| 7 | 6 | fveq2d 4685 |
. . . 4
    Top     
subSp  
   Top          subSp     Top      
   Top            |
| 8 | 5, 7 | opeq12d 3166 |
. . 3
    Top     
  subSp      Top          
    Top      
subSp     Top          Top             |
| 9 | 8 | eleq1d 1963 |
. 2
    Top     
  
subSp  
   Top          
TopSp     Top      
subSp     Top          Top          
TopSp  |
| 10 | | iftrue 2989 |
. . . . 5
  Top      Top          |
| 11 | | simpl 346 |
. . . . 5
  Top   Top |
| 12 | 10, 11 | eqeltrd 1971 |
. . . 4
  Top      Top        Top |
| 13 | | iffalse 2991 |
. . . . 5
  Top
 
   Top            |
| 14 | | sn0top 8917 |
. . . . 5
 
Top |
| 15 | 13, 14 | syl6eqel 1979 |
. . . 4
  Top
 
   Top        Top |
| 16 | 12, 15 | pm2.61i 140 |
. . 3
   Top
  
    Top |
| 17 | | iftrue 2989 |
. . . . 5
  Top      Top        |
| 18 | | sseq1 2637 |
. . . . . . 7
    Top     
    Top          Top            Top           |
| 19 | | unieq 3185 |
. . . . . . . 8
    Top            Top           |
| 20 | 19 | sseq2d 2645 |
. . . . . . 7
    Top             Top            |
| 21 | 18, 20 | sylan9bb 599 |
. . . . . 6
     Top     
   Top
  
         Top          Top            |
| 22 | | simpr 350 |
. . . . . 6
  Top      |
| 23 | 21, 22 | syl5cbir 228 |
. . . . 5
  Top        Top
  
     Top            Top          Top           |
| 24 | 17, 10, 23 | mp2and 767 |
. . . 4
  Top      Top          Top          |
| 25 | | iffalse 2991 |
. . . . 5
  Top
 
   Top        |
| 26 | | 0ss 2900 |
. . . . . 6
    |
| 27 | | sseq1 2637 |
. . . . . . 7
    Top          Top
  
      Top
  
        Top           |
| 28 | | unieq 3185 |
. . . . . . . 8
    Top              Top
  
         |
| 29 | 28 | sseq2d 2645 |
. . . . . . 7
    Top               Top              |
| 30 | 27, 29 | sylan9bb 599 |
. . . . . 6
     Top         Top               Top          Top              |
| 31 | 26, 30 | mpbiri 211 |
. . . . 5
     Top         Top              Top
  
      Top
  
      |
| 32 | 25, 13, 31 | syl11anc 524 |
. . . 4
  Top
 
   Top          Top          |
| 33 | 24, 32 | pm2.61i 140 |
. . 3
   Top
  
      Top
  
     |
| 34 | 16, 33 | stoiglem 10250 |
. 2
    Top
  
   subSp     Top          Top          
TopSp |
| 35 | 4, 9, 34 | dedth2v 3018 |
1
  Top     subSp      TopSp |