| Step | Hyp | Ref
| Expression |
| 1 | | cnextf.3 |
. . . 4
   |
| 2 | | cnextf.4 |
. . . 4
   |
| 3 | | cnextf.5 |
. . . 4
       |
| 4 | | cnextf.a |
. . . 4

  |
| 5 | | cnextf.1 |
. . . . 5
  |
| 6 | | cnextf.2 |
. . . . 5
  |
| 7 | 5, 6 | cnextfun 21868 |
. . . 4
             CnExt      |
| 8 | 1, 2, 3, 4, 7 | syl22anc 1327 |
. . 3
   CnExt      |
| 9 | | simpl 473 |
. . . . . . 7
 
   |
| 10 | | cnextf.6 |
. . . . . . . . 9
           |
| 11 | 10 | eleq2d 2687 |
. . . . . . . 8
             |
| 12 | 11 | biimpar 502 |
. . . . . . 7
 
           |
| 13 | | cnextf.7 |
. . . . . . . 8
 
             
↾t        |
| 14 | | n0 3931 |
. . . . . . . 8
             
↾t     
  
          
↾t        |
| 15 | 13, 14 | sylib 208 |
. . . . . . 7
 
   
          
↾t        |
| 16 | | haustop 21135 |
. . . . . . . . . . . . . 14

  |
| 17 | 2, 16 | syl 17 |
. . . . . . . . . . . . 13
   |
| 18 | 5, 6 | cnextfval 21866 |
. . . . . . . . . . . . 13
             CnExt                             
↾t         |
| 19 | 1, 17, 3, 4, 18 | syl22anc 1327 |
. . . . . . . . . . . 12
   CnExt                             
↾t         |
| 20 | 19 | eleq2d 2687 |
. . . . . . . . . . 11
       CnExt                                
↾t          |
| 21 | | opeliunxp 5170 |
. . . . . . . . . . 11
                             
↾t      
        
            
↾t         |
| 22 | 20, 21 | syl6bb 276 |
. . . . . . . . . 10
       CnExt            
            
↾t          |
| 23 | 22 | exbidv 1850 |
. . . . . . . . 9
         CnExt              
            
↾t          |
| 24 | | 19.42v 1918 |
. . . . . . . . 9
           
            
↾t      
                      
↾t         |
| 25 | 23, 24 | syl6bb 276 |
. . . . . . . 8
         CnExt                          
↾t          |
| 26 | 25 | biimpar 502 |
. . . . . . 7
 
                      
↾t               CnExt      |
| 27 | 9, 12, 15, 26 | syl12anc 1324 |
. . . . . 6
 
        CnExt      |
| 28 | 25 | simprbda 653 |
. . . . . . 7
 
       CnExt    
          |
| 29 | 11 | adantr 481 |
. . . . . . 7
 
       CnExt    
            |
| 30 | 28, 29 | mpbid 222 |
. . . . . 6
 
       CnExt    
  |
| 31 | 27, 30 | impbida 877 |
. . . . 5
         CnExt       |
| 32 | 31 | abbi2dv 2742 |
. . . 4
         CnExt       |
| 33 | | dfdm3 5310 |
. . . 4
  CnExt            CnExt      |
| 34 | 32, 33 | syl6reqr 2675 |
. . 3
   CnExt      |
| 35 | | df-fn 5891 |
. . 3
   CnExt       CnExt      CnExt       |
| 36 | 8, 34, 35 | sylanbrc 698 |
. 2
   CnExt      |
| 37 | 19 | rneqd 5353 |
. . 3
   CnExt                             
↾t         |
| 38 | | rniun 5543 |
. . . 4
                         
↾t                                
↾t        |
| 39 | | vex 3203 |
. . . . . . . . 9
 |
| 40 | 39 | snnz 4309 |
. . . . . . . 8
   |
| 41 | | rnxp 5564 |
. . . . . . . 8
                  
↾t                   
↾t        |
| 42 | 40, 41 | ax-mp 5 |
. . . . . . 7
               
↾t                   
↾t       |
| 43 | 11 | biimpa 501 |
. . . . . . . 8
 
        
  |
| 44 | 6 | toptopon 20722 |
. . . . . . . . . . 11

TopOn    |
| 45 | 17, 44 | sylib 208 |
. . . . . . . . . 10
 TopOn    |
| 46 | 45 | adantr 481 |
. . . . . . . . 9
 
 TopOn    |
| 47 | 5 | toptopon 20722 |
. . . . . . . . . . . 12

TopOn    |
| 48 | 1, 47 | sylib 208 |
. . . . . . . . . . 11
 TopOn    |
| 49 | 48 | adantr 481 |
. . . . . . . . . 10
 
 TopOn    |
| 50 | 4 | adantr 481 |
. . . . . . . . . 10
 
   |
| 51 | | simpr 477 |
. . . . . . . . . 10
 
   |
| 52 | | trnei 21696 |
. . . . . . . . . . 11
  TopOn           
          
↾t         |
| 53 | 52 | biimpa 501 |
. . . . . . . . . 10
   TopOn           
          
↾t        |
| 54 | 49, 50, 51, 12, 53 | syl31anc 1329 |
. . . . . . . . 9
 
           
↾t        |
| 55 | 3 | adantr 481 |
. . . . . . . . 9
 
       |
| 56 | | flfelbas 21798 |
. . . . . . . . . . 11
   TopOn            
↾t                       
↾t         |
| 57 | 56 | ex 450 |
. . . . . . . . . 10
  TopOn            
↾t             
          
↾t         |
| 58 | 57 | ssrdv 3609 |
. . . . . . . . 9
  TopOn            
↾t                       
↾t        |
| 59 | 46, 54, 55, 58 | syl3anc 1326 |
. . . . . . . 8
 
             
↾t        |
| 60 | 43, 59 | syldan 487 |
. . . . . . 7
 
        
             ↾t        |
| 61 | 42, 60 | syl5eqss 3649 |
. . . . . 6
 
        
               
↾t         |
| 62 | 61 | ralrimiva 2966 |
. . . . 5
                          
↾t         |
| 63 | | iunss 4561 |
. . . . 5
 
                        
↾t                                
↾t         |
| 64 | 62, 63 | sylibr 224 |
. . . 4
                          
↾t         |
| 65 | 38, 64 | syl5eqss 3649 |
. . 3
                          
↾t         |
| 66 | 37, 65 | eqsstrd 3639 |
. 2
   CnExt   
  |
| 67 | | df-f 5892 |
. 2
   CnExt       
   CnExt      CnExt       |
| 68 | 36, 66, 67 | sylanbrc 698 |
1
   CnExt          |