Step |
Hyp |
Ref |
Expression |
1 |
|
simpr |
|
2 |
|
cnex |
|
3 |
|
ssexg |
|
4 |
1 2 3
|
sylancl |
|
5 |
|
snex |
|
6 |
|
unexg |
|
7 |
4 5 6
|
sylancl |
|
8 |
|
unss1 |
|
9 |
8
|
adantr |
|
10 |
|
mapss |
|
11 |
7 9 10
|
syl2anc |
|
12 |
|
ssrexv |
|
13 |
11 12
|
syl |
|
14 |
13
|
reximdv |
|
15 |
14
|
ss2abdv |
|
16 |
|
sstr |
|
17 |
|
plyval |
|
18 |
16 17
|
syl |
|
19 |
|
plyval |
|
20 |
19
|
adantl |
|
21 |
15 18 20
|
3sstr4d |
|