Step |
Hyp |
Ref |
Expression |
1 |
|
nnon |
|
2 |
|
onnbtwn |
|
3 |
1 2
|
syl |
|
4 |
3
|
3ad2ant1 |
|
5 |
|
suceq |
|
6 |
5
|
eqeq1d |
|
7 |
6
|
3ad2ant3 |
|
8 |
|
ovex |
|
9 |
8
|
sucid |
|
10 |
|
eleq2 |
|
11 |
9 10
|
mpbii |
|
12 |
|
2onn |
|
13 |
|
nnmord |
|
14 |
12 13
|
mp3an3 |
|
15 |
|
simpl |
|
16 |
14 15
|
syl6bir |
|
17 |
11 16
|
syl5 |
|
18 |
|
simpr |
|
19 |
|
nnmcl |
|
20 |
12 19
|
mpan |
|
21 |
|
nnon |
|
22 |
|
oa1suc |
|
23 |
20 21 22
|
3syl |
|
24 |
|
1oex |
|
25 |
24
|
sucid |
|
26 |
|
df-2o |
|
27 |
25 26
|
eleqtrri |
|
28 |
|
1onn |
|
29 |
|
nnaord |
|
30 |
28 12 20 29
|
mp3an12i |
|
31 |
27 30
|
mpbii |
|
32 |
|
nnmsuc |
|
33 |
12 32
|
mpan |
|
34 |
31 33
|
eleqtrrd |
|
35 |
23 34
|
eqeltrrd |
|
36 |
35
|
ad2antrr |
|
37 |
18 36
|
eqeltrrd |
|
38 |
|
peano2 |
|
39 |
|
nnmord |
|
40 |
12 39
|
mp3an3 |
|
41 |
38 40
|
sylan2 |
|
42 |
41
|
ancoms |
|
43 |
42
|
adantr |
|
44 |
37 43
|
mpbird |
|
45 |
44
|
simpld |
|
46 |
45
|
ex |
|
47 |
17 46
|
jcad |
|
48 |
47
|
3adant3 |
|
49 |
7 48
|
sylbid |
|
50 |
4 49
|
mtod |
|