Step |
Hyp |
Ref |
Expression |
1 |
|
eqer.1 |
|
2 |
|
eqer.2 |
|
3 |
2
|
brabsb |
|
4 |
|
nfcsb1v |
|
5 |
|
nfcsb1v |
|
6 |
4 5
|
nfeq |
|
7 |
|
nfv |
|
8 |
|
vex |
|
9 |
8 1
|
csbie |
|
10 |
|
csbeq1 |
|
11 |
9 10
|
syl5eqr |
|
12 |
11
|
eqeq2d |
|
13 |
7 12
|
sbciegf |
|
14 |
13
|
elv |
|
15 |
|
csbeq1a |
|
16 |
15
|
eqeq1d |
|
17 |
14 16
|
syl5bb |
|
18 |
6 17
|
sbciegf |
|
19 |
18
|
elv |
|
20 |
3 19
|
bitri |
|