Proof of Theorem clsun
| Step | Hyp | Ref
| Expression |
| 1 | | difss 2735 |
. . . . . . 7

  |
| 2 | | difss 2735 |
. . . . . . 7

  |
| 3 | | clsun.1 |
. . . . . . . 8
  |
| 4 | 3 | ntrin 15411 |
. . . . . . 7
  Top   
   int             int    
   int          |
| 5 | 1, 2, 4 | mp3an23 1183 |
. . . . . 6
 Top
 int             int    
   int          |
| 6 | 5 | 3ad2ant1 897 |
. . . . 5
  Top   int             int    
   int          |
| 7 | | difundi 2847 |
. . . . . 6

          |
| 8 | 7 | fveq2i 4684 |
. . . . 5
 int          int            |
| 9 | 6, 8 | syl5eq 1940 |
. . . 4
  Top   int           int    
   int          |
| 10 | | simp1 876 |
. . . . 5
  Top  Top |
| 11 | | unss 2780 |
. . . . . . 7
 
     |
| 12 | 11 | biimpi 168 |
. . . . . 6
 
     |
| 13 | 12 | 3adant1 894 |
. . . . 5
  Top  
   |
| 14 | 3 | ntrcmp 15406 |
. . . . 5
  Top     int           cls          |
| 15 | 10, 13, 14 | syl11anc 524 |
. . . 4
  Top   int           cls          |
| 16 | 3 | ntrcmp 15406 |
. . . . . . 7
  Top   int         cls        |
| 17 | 16 | 3adant3 896 |
. . . . . 6
  Top   int         cls        |
| 18 | 3 | ntrcmp 15406 |
. . . . . . 7
  Top   int         cls        |
| 19 | 18 | 3adant2 895 |
. . . . . 6
  Top   int         cls        |
| 20 | 17, 19 | ineq12d 2797 |
. . . . 5
  Top    int        int           cls        cls         |
| 21 | | difundi 2847 |
. . . . 5

  cls      cls          cls        cls        |
| 22 | 20, 21 | syl6eqr 1946 |
. . . 4
  Top    int        int           cls    
 cls         |
| 23 | 9, 15, 22 | 3eqtr3d 1934 |
. . 3
  Top  
 cls           cls      cls         |
| 24 | 23 | difeq2d 2726 |
. 2
  Top  
  cls    
     
  cls      cls          |
| 25 | 3 | clscld 8959 |
. . . . 5
  Top     cls       Clsd    |
| 26 | 10, 13, 25 | syl11anc 524 |
. . . 4
  Top   cls       Clsd    |
| 27 | 3 | cldss 8947 |
. . . 4
  Top  cls       Clsd    cls         |
| 28 | 10, 26, 27 | syl11anc 524 |
. . 3
  Top   cls         |
| 29 | | dfss4 2827 |
. . 3
  cls        
 cls          cls    
    |
| 30 | 28, 29 | sylib 215 |
. 2
  Top  
  cls    
     cls         |
| 31 | 3 | clsss3 8967 |
. . . . 5
  Top   cls       |
| 32 | 31 | 3adant3 896 |
. . . 4
  Top   cls       |
| 33 | 3 | clsss3 8967 |
. . . . 5
  Top   cls       |
| 34 | 33 | 3adant2 895 |
. . . 4
  Top   cls       |
| 35 | 32, 34 | jca 310 |
. . 3
  Top    cls    
 cls        |
| 36 | | unss 2780 |
. . . 4
   cls      cls        cls      cls        |
| 37 | | dfss4 2827 |
. . . 4
   cls    
 cls       
  cls      cls          cls      cls        |
| 38 | 36, 37 | bitri 190 |
. . 3
   cls      cls          cls    
 cls          cls      cls        |
| 39 | 35, 38 | sylib 215 |
. 2
  Top  
   cls      cls          cls      cls        |
| 40 | 24, 30, 39 | 3eqtr3d 1934 |
1
  Top   cls         cls    
 cls        |