Step |
Hyp |
Ref |
Expression |
1 |
|
lautset.b |
|
2 |
|
lautset.l |
|
3 |
|
lautset.i |
|
4 |
1 2 3
|
lautset |
|
5 |
4
|
eleq2d |
|
6 |
|
f1of |
|
7 |
1
|
fvexi |
|
8 |
|
fex |
|
9 |
6 7 8
|
sylancl |
|
10 |
9
|
adantr |
|
11 |
|
f1oeq1 |
|
12 |
|
fveq1 |
|
13 |
|
fveq1 |
|
14 |
12 13
|
breq12d |
|
15 |
14
|
bibi2d |
|
16 |
15
|
2ralbidv |
|
17 |
11 16
|
anbi12d |
|
18 |
10 17
|
elab3 |
|
19 |
5 18
|
bitrdi |
|