Step |
Hyp |
Ref |
Expression |
1 |
|
oppgbas.1 |
|
2 |
|
oppginv.2 |
|
3 |
|
eqid |
|
4 |
3 2
|
grpinvf |
|
5 |
|
eqid |
|
6 |
|
eqid |
|
7 |
5 1 6
|
oppgplus |
|
8 |
|
eqid |
|
9 |
3 5 8 2
|
grprinv |
|
10 |
7 9
|
syl5eq |
|
11 |
10
|
ralrimiva |
|
12 |
1
|
oppggrp |
|
13 |
1 3
|
oppgbas |
|
14 |
1 8
|
oppgid |
|
15 |
|
eqid |
|
16 |
13 6 14 15
|
isgrpinv |
|
17 |
12 16
|
syl |
|
18 |
4 11 17
|
mpbi2and |
|
19 |
18
|
eqcomd |
|