Step |
Hyp |
Ref |
Expression |
1 |
|
sssucid |
|
2 |
|
id |
|
3 |
|
id |
|
4 |
3
|
simpld |
|
5 |
|
id |
|
6 |
2 4 5
|
trelded |
|
7 |
1 6
|
sseldi |
|
8 |
7
|
3expia |
|
9 |
|
id |
|
10 |
|
eleq2 |
|
11 |
10
|
biimpac |
|
12 |
4 9 11
|
syl2an |
|
13 |
1 12
|
sseldi |
|
14 |
13
|
ex |
|
15 |
3
|
simprd |
|
16 |
|
elsuci |
|
17 |
15 16
|
syl |
|
18 |
8 14 17
|
jaoded |
|
19 |
18
|
un2122 |
|
20 |
19
|
ex |
|
21 |
20
|
alrimivv |
|
22 |
|
dftr2 |
|
23 |
22
|
biimpri |
|
24 |
21 23
|
syl |
|
25 |
24
|
idiALT |
|