Proof of Theorem gafo
| Step | Hyp | Ref
| Expression |
| 1 | | gafo.1 |
. . . . 5
 |
| 2 | | gafo.2 |
. . . . 5
 |
| 3 | | eqid 1884 |
. . . . 5
Id  Id   |
| 4 | 1, 2, 3 | isga 9450 |
. . . 4

   
GrpAct  Grp      

  Id     

                     |
| 5 | 4 | biimpa 460 |
. . 3
     GrpAct  Grp      

  Id     

                    |
| 6 | | ffn 4562 |
. . . . 5
      
    |
| 7 | 6 | 3ad2ant2 898 |
. . . 4
  Grp      

  Id     

                      |
| 8 | | frn 4569 |
. . . . . 6
      
  |
| 9 | 8 | 3ad2ant2 898 |
. . . . 5
  Grp      

  Id     

                 
  |
| 10 | | ax-17 1317 |
. . . . . . . 8
 Grp

Grp |
| 11 | | ax-17 1317 |
. . . . . . . 8
      
         |
| 12 | | hbra1 2147 |
. . . . . . . 8
    Id                          
  Id     

                   |
| 13 | 10, 11, 12 | hb3an 1359 |
. . . . . . 7
  Grp      

  Id     

                     Grp       
  Id     

                    |
| 14 | | ra4 2155 |
. . . . . . . . . 10
    Id                           Id     

                    |
| 15 | | simpl2l 929 |
. . . . . . . . . . . 12
     Id     

                 Grp
        Id       |
| 16 | 6 | adantl 424 |
. . . . . . . . . . . . 13
     Id     

                 Grp
           |
| 17 | 1, 3 | grpidcl 9343 |
. . . . . . . . . . . . . . 15
 Grp
Id    |
| 18 | 17 | 3ad2ant3 899 |
. . . . . . . . . . . . . 14
    Id                        Grp Id    |
| 19 | 18 | adantr 425 |
. . . . . . . . . . . . 13
     Id     

                 Grp
       Id 
  |
| 20 | | simpl1 879 |
. . . . . . . . . . . . 13
     Id     

                 Grp
         |
| 21 | | fnoprvrn 4968 |
. . . . . . . . . . . . 13
    Id 
  Id       |
| 22 | 16, 19, 20, 21 | syl111anc 1100 |
. . . . . . . . . . . 12
     Id     

                 Grp
        Id       |
| 23 | 15, 22 | eqeltrrd 1972 |
. . . . . . . . . . 11
     Id     

                 Grp
         |
| 24 | 23 | 3exp1 1084 |
. . . . . . . . . 10

   Id                         Grp             |
| 25 | 14, 24 | sylcom 62 |
. . . . . . . . 9
    Id                          Grp             |
| 26 | 25 | com4t 44 |
. . . . . . . 8
 Grp
      
 
  Id     

                       |
| 27 | 26 | 3imp 1061 |
. . . . . . 7
  Grp      

  Id     

                      |
| 28 | 13, 27 | 19.21ai 1345 |
. . . . . 6
  Grp      

  Id     

                    
   |
| 29 | | dfss2 2610 |
. . . . . 6
       |
| 30 | 28, 29 | sylibr 217 |
. . . . 5
  Grp      

  Id     

                    |
| 31 | 9, 30 | eqssd 2633 |
. . . 4
  Grp      

  Id     

                 
  |
| 32 | 7, 31 | jca 310 |
. . 3
  Grp      

  Id     

                        |
| 33 | 5, 32 | syl 12 |
. 2
     GrpAct       |
| 34 | | df-fo 4012 |
. 2
             |
| 35 | 33, 34 | sylibr 217 |
1
     GrpAct         |