| Step |
Hyp |
Ref |
Expression |
| 1 |
|
mulgsubdir.b |
|
| 2 |
|
mulgsubdir.t |
|
| 3 |
|
mulgsubdir.d |
|
| 4 |
|
znegcl |
|
| 5 |
|
eqid |
|
| 6 |
1 2 5
|
mulgdir |
|
| 7 |
4 6
|
syl3anr2 |
|
| 8 |
|
simpr1 |
|
| 9 |
8
|
zcnd |
|
| 10 |
|
simpr2 |
|
| 11 |
10
|
zcnd |
|
| 12 |
9 11
|
negsubd |
|
| 13 |
12
|
oveq1d |
|
| 14 |
|
eqid |
|
| 15 |
1 2 14
|
mulgneg |
|
| 16 |
15
|
3adant3r1 |
|
| 17 |
16
|
oveq2d |
|
| 18 |
1 2
|
mulgcl |
|
| 19 |
18
|
3adant3r2 |
|
| 20 |
1 2
|
mulgcl |
|
| 21 |
20
|
3adant3r1 |
|
| 22 |
1 5 14 3
|
grpsubval |
|
| 23 |
19 21 22
|
syl2anc |
|
| 24 |
17 23
|
eqtr4d |
|
| 25 |
7 13 24
|
3eqtr3d |
|