Step |
Hyp |
Ref |
Expression |
1 |
|
eleq1 |
|
2 |
1
|
eqcoms |
|
3 |
2
|
biimpa |
|
4 |
|
nnel |
|
5 |
3 4
|
sylibr |
|
6 |
5
|
a1d |
|
7 |
|
simpl |
|
8 |
7
|
a1d |
|
9 |
6 8
|
jca |
|
10 |
9
|
ex |
|
11 |
|
eleq1 |
|
12 |
11
|
anbi2d |
|
13 |
|
elnelall |
|
14 |
13
|
impcom |
|
15 |
12 14
|
syl6bir |
|
16 |
15
|
com12 |
|
17 |
|
pm2.24 |
|
18 |
17
|
adantr |
|
19 |
16 18
|
jca |
|
20 |
19
|
ex |
|
21 |
10 20
|
jaoi |
|
22 |
21
|
com12 |
|
23 |
|
df-xor |
|
24 |
|
xor3 |
|
25 |
|
dfbi2 |
|
26 |
23 24 25
|
3bitri |
|
27 |
22 26
|
syl6ibr |
|
28 |
|
xoror |
|
29 |
27 28
|
impbid1 |
|