Step |
Hyp |
Ref |
Expression |
1 |
|
str.1 |
|
2 |
|
str.2 |
|
3 |
|
dfral2 |
|
4 |
1 2
|
strlem1 |
|
5 |
|
eqid |
|
6 |
|
biid |
|
7 |
5 6 1 2
|
strlem3 |
|
8 |
5 6 1 2
|
strlem6 |
|
9 |
|
fveq1 |
|
10 |
9
|
eqeq1d |
|
11 |
|
fveq1 |
|
12 |
11
|
eqeq1d |
|
13 |
10 12
|
imbi12d |
|
14 |
13
|
notbid |
|
15 |
14
|
rspcev |
|
16 |
7 8 15
|
syl2anc |
|
17 |
16
|
rexlimiva |
|
18 |
4 17
|
syl |
|
19 |
18
|
con1i |
|
20 |
3 19
|
sylbi |
|