| Step |
Hyp |
Ref |
Expression |
| 1 |
|
peano1 |
|
| 2 |
|
elelsuc |
|
| 3 |
|
satf0sucom |
|
| 4 |
1 2 3
|
mp2b |
|
| 5 |
|
omex |
|
| 6 |
5 5
|
xpex |
|
| 7 |
|
xpexg |
|
| 8 |
|
simpl |
|
| 9 |
|
goelel3xp |
|
| 10 |
|
eleq1 |
|
| 11 |
9 10
|
syl5ibrcom |
|
| 12 |
11
|
rexlimivv |
|
| 13 |
12
|
ad2antll |
|
| 14 |
|
eleq1 |
|
| 15 |
1 14
|
mpbiri |
|
| 16 |
15
|
ad2antrl |
|
| 17 |
7 8 13 16
|
opabex2 |
|
| 18 |
5 6 17
|
mp2an |
|
| 19 |
18
|
rdg0 |
|
| 20 |
4 19
|
eqtri |
|