| Step | Hyp | Ref
| Expression |
| 1 | | df-igsum 12961 |
. . 3
g                                          |
| 2 | 1 | a1i 9 |
. 2
 g                                           |
| 3 | | simprr 531 |
. . . . . . . 8
 

    |
| 4 | 3 | dmeqd 4869 |
. . . . . . 7
 

 
  |
| 5 | | gsumvalx.a |
. . . . . . . 8
   |
| 6 | 5 | adantr 276 |
. . . . . . 7
 

    |
| 7 | 4, 6 | eqtrd 2229 |
. . . . . 6
 

 
  |
| 8 | 7 | eqeq1d 2205 |
. . . . 5
 

  
   |
| 9 | | simprl 529 |
. . . . . . . 8
 

 
  |
| 10 | 9 | fveq2d 5565 |
. . . . . . 7
 

            |
| 11 | | gsumval.z |
. . . . . . 7
     |
| 12 | 10, 11 | eqtr4di 2247 |
. . . . . 6
 

       |
| 13 | 12 | eqeq2d 2208 |
. . . . 5
 

         |
| 14 | 8, 13 | anbi12d 473 |
. . . 4
 

        
    |
| 15 | 7 | eqeq1d 2205 |
. . . . . . 7
 

  
   
       |
| 16 | | eqidd 2197 |
. . . . . . . . . 10
 

 
  |
| 17 | 9 | fveq2d 5565 |
. . . . . . . . . . 11
 

  
       |
| 18 | | gsumval.p |
. . . . . . . . . . 11
    |
| 19 | 17, 18 | eqtr4di 2247 |
. . . . . . . . . 10
 

  
   |
| 20 | 16, 19, 3 | seqeq123d 10565 |
. . . . . . . . 9
 

           
   |
| 21 | 20 | fveq1d 5563 |
. . . . . . . 8
 

                     |
| 22 | 21 | eqeq2d 2208 |
. . . . . . 7
 

             
         |
| 23 | 15, 22 | anbi12d 473 |
. . . . . 6
 

       
                           |
| 24 | 23 | rexbidv 2498 |
. . . . 5
 

         
   
           
                     |
| 25 | 24 | exbidv 1839 |
. . . 4
 

     
         
                                   |
| 26 | 14, 25 | orbi12d 794 |
. . 3
 

                  
   
                 
         
           |
| 27 | 26 | iotabidv 5242 |
. 2
 

              
         
                                           |
| 28 | | gsumval.g |
. . 3
   |
| 29 | 28 | elexd 2776 |
. 2
   |
| 30 | | gsumvalx.f |
. . 3
   |
| 31 | 30 | elexd 2776 |
. 2
   |
| 32 | | unab 3431 |
. . . 4
  
    
         
              
         
          |
| 33 | | df-sn 3629 |
. . . . . . 7
  |
| 34 | | fn0g 13077 |
. . . . . . . . . 10
 |
| 35 | | funfvex 5578 |
. . . . . . . . . . 11
         |
| 36 | 35 | funfni 5361 |
. . . . . . . . . 10
 
       |
| 37 | 34, 29, 36 | sylancr 414 |
. . . . . . . . 9
       |
| 38 | 11, 37 | eqeltrid 2283 |
. . . . . . . 8
   |
| 39 | | snexg 4218 |
. . . . . . . 8
  |
| 40 | 38, 39 | syl 14 |
. . . . . . 7
   |
| 41 | 33, 40 | eqeltrrid 2284 |
. . . . . 6
    |
| 42 | | simpr 110 |
. . . . . . . 8
   |
| 43 | 42 | ss2abi 3256 |
. . . . . . 7
   
 |
| 44 | 43 | a1i 9 |
. . . . . 6
       |
| 45 | 41, 44 | ssexd 4174 |
. . . . 5
      |
| 46 | | zex 9352 |
. . . . . . 7
 |
| 47 | 46, 46 | ab2rexex 6197 |
. . . . . 6
  
 
    
 |
| 48 | | df-rex 2481 |
. . . . . . . . . . . 12
           
 
           
    
 
        |
| 49 | | eluzel2 9623 |
. . . . . . . . . . . . . . . 16
    
  |
| 50 | | eluzelz 9627 |
. . . . . . . . . . . . . . . 16
    
  |
| 51 | 49, 50 | jca 306 |
. . . . . . . . . . . . . . 15
    
    |
| 52 | | simpr 110 |
. . . . . . . . . . . . . . 15
     
      
 
      |
| 53 | 51, 52 | anim12i 338 |
. . . . . . . . . . . . . 14
      
   
 
                  |
| 54 | | anass 401 |
. . . . . . . . . . . . . 14
          
 
 
        |
| 55 | 53, 54 | sylib 122 |
. . . . . . . . . . . . 13
      
   
 
       
          |
| 56 | 55 | eximi 1614 |
. . . . . . . . . . . 12
                        
 
        |
| 57 | 48, 56 | sylbi 121 |
. . . . . . . . . . 11
           
 
    
              |
| 58 | | 19.42v 1921 |
. . . . . . . . . . 11
    
 
     
              |
| 59 | 57, 58 | sylib 122 |
. . . . . . . . . 10
           
 
    
              |
| 60 | | df-rex 2481 |
. . . . . . . . . . 11
 
 
                |
| 61 | 60 | anbi2i 457 |
. . . . . . . . . 10
  
 
                   |
| 62 | 59, 61 | sylibr 134 |
. . . . . . . . 9
           
 
    
           |
| 63 | 62 | eximi 1614 |
. . . . . . . 8
                        
         |
| 64 | | df-rex 2481 |
. . . . . . . 8
  
 
                 |
| 65 | 63, 64 | sylibr 134 |
. . . . . . 7
                               |
| 66 | 65 | ss2abi 3256 |
. . . . . 6
                                 |
| 67 | 47, 66 | ssexi 4172 |
. . . . 5
                       |
| 68 | | unexg 4479 |
. . . . 5
                           
  
    
         
           |
| 69 | 45, 67, 68 | sylancl 413 |
. . . 4
    
                         |
| 70 | 32, 69 | eqeltrrid 2284 |
. . 3
                            |
| 71 | | iotaexab 5238 |
. . 3
                
             
            
           |
| 72 | 70, 71 | syl 14 |
. 2
                              |
| 73 | 2, 27, 29, 31, 72 | ovmpod 6054 |
1
  g                   
           |