Step |
Hyp |
Ref |
Expression |
1 |
|
df-bj-2upl |
|
2 |
|
bj-pr2eq |
|
3 |
1 2
|
ax-mp |
|
4 |
|
bj-pr2un |
|
5 |
3 4
|
eqtri |
|
6 |
|
df-bj-1upl |
|
7 |
|
bj-pr2eq |
|
8 |
6 7
|
ax-mp |
|
9 |
|
bj-pr2val |
|
10 |
|
1n0 |
|
11 |
10
|
nesymi |
|
12 |
11
|
iffalsei |
|
13 |
8 9 12
|
3eqtri |
|
14 |
|
bj-pr2val |
|
15 |
|
eqid |
|
16 |
15
|
iftruei |
|
17 |
14 16
|
eqtri |
|
18 |
13 17
|
uneq12i |
|
19 |
|
0un |
|
20 |
5 18 19
|
3eqtri |
|