Step |
Hyp |
Ref |
Expression |
1 |
|
eqer.1 |
|
2 |
|
eqer.2 |
|
3 |
2
|
relopabi |
|
4 |
|
id |
|
5 |
4
|
eqcomd |
|
6 |
1 2
|
eqerlem |
|
7 |
1 2
|
eqerlem |
|
8 |
5 6 7
|
3imtr4i |
|
9 |
|
eqtr |
|
10 |
1 2
|
eqerlem |
|
11 |
6 10
|
anbi12i |
|
12 |
1 2
|
eqerlem |
|
13 |
9 11 12
|
3imtr4i |
|
14 |
|
vex |
|
15 |
|
eqid |
|
16 |
1 2
|
eqerlem |
|
17 |
15 16
|
mpbir |
|
18 |
14 17
|
2th |
|
19 |
3 8 13 18
|
iseri |
|