Step |
Hyp |
Ref |
Expression |
1 |
|
xrltletr |
|
2 |
|
id |
|
3 |
2
|
impcom |
|
4 |
|
xrltnle |
|
5 |
4
|
3adant2 |
|
6 |
5
|
biimpd |
|
7 |
6
|
imp |
|
8 |
7
|
olcd |
|
9 |
8
|
expcom |
|
10 |
3 9
|
syl |
|
11 |
10
|
ex |
|
12 |
11
|
com23 |
|
13 |
12
|
impd |
|
14 |
|
id |
|
15 |
14
|
orcd |
|
16 |
15
|
a1d |
|
17 |
13 16
|
pm2.61i |
|
18 |
|
df-3an |
|
19 |
18
|
notbii |
|
20 |
|
ianor |
|
21 |
19 20
|
bitri |
|
22 |
17 21
|
sylibr |
|
23 |
22
|
ex |
|
24 |
1 23
|
mpd |
|