| Step |
Hyp |
Ref |
Expression |
| 1 |
|
difeq2 |
|
| 2 |
1
|
eleq1d |
|
| 3 |
2
|
elrab |
|
| 4 |
|
difeq2 |
|
| 5 |
4
|
eleq1d |
|
| 6 |
5
|
elrab |
|
| 7 |
|
an4 |
|
| 8 |
7
|
biimpi |
|
| 9 |
3 6 8
|
syl2anb |
|
| 10 |
|
sorpssi |
|
| 11 |
10
|
expcom |
|
| 12 |
|
velpw |
|
| 13 |
|
dfss4 |
|
| 14 |
12 13
|
bitri |
|
| 15 |
|
velpw |
|
| 16 |
|
dfss4 |
|
| 17 |
15 16
|
bitri |
|
| 18 |
|
sscon |
|
| 19 |
|
sseq12 |
|
| 20 |
18 19
|
imbitrid |
|
| 21 |
|
sscon |
|
| 22 |
|
sseq12 |
|
| 23 |
22
|
ancoms |
|
| 24 |
21 23
|
imbitrid |
|
| 25 |
20 24
|
orim12d |
|
| 26 |
14 17 25
|
syl2anb |
|
| 27 |
26
|
com12 |
|
| 28 |
27
|
orcoms |
|
| 29 |
11 28
|
syl6 |
|
| 30 |
29
|
com3l |
|
| 31 |
30
|
impd |
|
| 32 |
9 31
|
syl5 |
|
| 33 |
32
|
ralrimivv |
|
| 34 |
|
sorpss |
|
| 35 |
33 34
|
sylibr |
|