Proof of Theorem drngi
| Step | Hyp | Ref
| Expression |
| 1 | | df-drng 9492 |
. . . 4
DivRing         Ring     Id      Id      Grp  |
| 2 | 1 | eleq2i 1961 |
. . 3

DivRing         Ring     Id      Id      Grp   |
| 3 | | opeq1 3158 |
. . . . . 6
                 |
| 4 | 3 | eleq1d 1963 |
. . . . 5
         Ring        Ring  |
| 5 | | id 73 |
. . . . . . . . . . . . 13
           |
| 6 | | drngi.1 |
. . . . . . . . . . . . 13
     |
| 7 | 5, 6 | syl6eqr 1946 |
. . . . . . . . . . . 12
       |
| 8 | 7 | rneqd 4188 |
. . . . . . . . . . 11
    
  |
| 9 | | drngi.3 |
. . . . . . . . . . 11
 |
| 10 | 8, 9 | syl6eqr 1946 |
. . . . . . . . . 10
    
  |
| 11 | 10 | difeq1d 2725 |
. . . . . . . . 9
       Id      Id      |
| 12 | 7 | fveq2d 4685 |
. . . . . . . . . . . 12
     Id  Id    |
| 13 | | drngi.4 |
. . . . . . . . . . . 12
Id   |
| 14 | 12, 13 | syl6eqr 1946 |
. . . . . . . . . . 11
     Id    |
| 15 | 14 | sneqd 3056 |
. . . . . . . . . 10
      Id       |
| 16 | 15 | difeq2d 2726 |
. . . . . . . . 9
       Id          |
| 17 | 11, 16 | eqtrd 1925 |
. . . . . . . 8
       Id          |
| 18 | | xpeq2 4017 |
. . . . . . . . 9
   Id           Id      Id        Id           |
| 19 | | xpeq1 4016 |
. . . . . . . . 9
   Id           Id                     |
| 20 | 18, 19 | eqtrd 1925 |
. . . . . . . 8
   Id           Id      Id                 |
| 21 | 17, 20 | syl 12 |
. . . . . . 7
        Id      Id                 |
| 22 | | reseq2 4219 |
. . . . . . 7
    Id      Id                   Id      Id                    |
| 23 | 21, 22 | syl 12 |
. . . . . 6
         Id      Id                    |
| 24 | 23 | eleq1d 1963 |
. . . . 5
          Id      Id      Grp             Grp  |
| 25 | 4, 24 | anbi12d 690 |
. . . 4
          Ring     Id      Id      Grp         Ring             Grp   |
| 26 | | opeq2 3159 |
. . . . . . 7
          
              |
| 27 | 26 | eleq1d 1963 |
. . . . . 6
             Ring            Ring  |
| 28 | 27 | anbi1d 679 |
. . . . 5
              Ring             Grp       
     Ring             Grp   |
| 29 | | id 73 |
. . . . . . . . 9
           |
| 30 | | drngi.2 |
. . . . . . . . 9
     |
| 31 | 29, 30 | syl6reqr 1947 |
. . . . . . . 8
       |
| 32 | | reseq1 4218 |
. . . . . . . 8
                           |
| 33 | 31, 32 | syl 12 |
. . . . . . 7
                               |
| 34 | 33 | eleq1d 1963 |
. . . . . 6
                  Grp             Grp  |
| 35 | 34 | anbi2d 678 |
. . . . 5
                  Ring             Grp             Ring             Grp   |
| 36 | 28, 35 | bitr4d 590 |
. . . 4
              Ring             Grp       
     Ring             Grp   |
| 37 | 25, 36 | elopabi 5059 |
. . 3

  
     Ring     Id      Id      Grp             Ring             Grp  |
| 38 | 2, 37 | sylbi 216 |
. 2

DivRing       
     Ring             Grp  |
| 39 | | relopab 4104 |
. . . . . 6
        Ring     Id      Id      Grp  |
| 40 | 1 | releqi 4072 |
. . . . . 6
 DivRing         Ring     Id      Id      Grp   |
| 41 | 39, 40 | mpbir 207 |
. . . . 5
DivRing |
| 42 | | 1st2nd 5048 |
. . . . 5
  DivRing
DivRing      
       |
| 43 | 41, 42 | mpan 759 |
. . . 4

DivRing      
       |
| 44 | 43 | eleq1d 1963 |
. . 3

DivRing  Ring            Ring  |
| 45 | 44 | anbi1d 679 |
. 2

DivRing   Ring             Grp             Ring             Grp   |
| 46 | 38, 45 | mpbird 213 |
1

DivRing  Ring
            Grp  |