Step |
Hyp |
Ref |
Expression |
1 |
|
preq1b.a |
|
2 |
|
preq1b.b |
|
3 |
|
prid1g |
|
4 |
1 3
|
syl |
|
5 |
|
eleq2 |
|
6 |
4 5
|
syl5ibcom |
|
7 |
|
elprg |
|
8 |
1 7
|
syl |
|
9 |
6 8
|
sylibd |
|
10 |
9
|
imp |
|
11 |
|
prid1g |
|
12 |
2 11
|
syl |
|
13 |
|
eleq2 |
|
14 |
12 13
|
syl5ibrcom |
|
15 |
|
elprg |
|
16 |
2 15
|
syl |
|
17 |
14 16
|
sylibd |
|
18 |
17
|
imp |
|
19 |
|
eqcom |
|
20 |
|
eqeq2 |
|
21 |
10 18 19 20
|
oplem1 |
|
22 |
21
|
ex |
|
23 |
|
preq1 |
|
24 |
22 23
|
impbid1 |
|