Step |
Hyp |
Ref |
Expression |
1 |
|
elex |
|
2 |
1
|
adantr |
|
3 |
|
elex |
|
4 |
3
|
adantl |
|
5 |
|
funmpt |
|
6 |
5
|
a1i |
|
7 |
|
dftpos4 |
|
8 |
|
tposexg |
|
9 |
8
|
adantr |
|
10 |
7 9
|
eqeltrrid |
|
11 |
|
dftpos4 |
|
12 |
|
tposexg |
|
13 |
12
|
adantl |
|
14 |
11 13
|
eqeltrrid |
|
15 |
|
ofco2 |
|
16 |
2 4 6 10 14 15
|
syl23anc |
|
17 |
|
dftpos4 |
|
18 |
7 11
|
oveq12i |
|
19 |
16 17 18
|
3eqtr4g |
|