Step |
Hyp |
Ref |
Expression |
1 |
|
0ss |
|- (/) C_ B |
2 |
|
sspsstr |
|- ( ( (/) C_ B /\ B C. A ) -> (/) C. A ) |
3 |
1 2
|
mpan |
|- ( B C. A -> (/) C. A ) |
4 |
|
0pss |
|- ( (/) C. A <-> A =/= (/) ) |
5 |
|
df-ne |
|- ( A =/= (/) <-> -. A = (/) ) |
6 |
4 5
|
bitri |
|- ( (/) C. A <-> -. A = (/) ) |
7 |
3 6
|
sylib |
|- ( B C. A -> -. A = (/) ) |
8 |
|
nn0suc |
|- ( A e. _om -> ( A = (/) \/ E. x e. _om A = suc x ) ) |
9 |
8
|
orcanai |
|- ( ( A e. _om /\ -. A = (/) ) -> E. x e. _om A = suc x ) |
10 |
7 9
|
sylan2 |
|- ( ( A e. _om /\ B C. A ) -> E. x e. _om A = suc x ) |
11 |
|
pssnel |
|- ( B C. suc x -> E. y ( y e. suc x /\ -. y e. B ) ) |
12 |
|
pssss |
|- ( B C. suc x -> B C_ suc x ) |
13 |
|
ssdif |
|- ( B C_ suc x -> ( B \ { y } ) C_ ( suc x \ { y } ) ) |
14 |
|
disjsn |
|- ( ( B i^i { y } ) = (/) <-> -. y e. B ) |
15 |
|
disj3 |
|- ( ( B i^i { y } ) = (/) <-> B = ( B \ { y } ) ) |
16 |
14 15
|
bitr3i |
|- ( -. y e. B <-> B = ( B \ { y } ) ) |
17 |
|
sseq1 |
|- ( B = ( B \ { y } ) -> ( B C_ ( suc x \ { y } ) <-> ( B \ { y } ) C_ ( suc x \ { y } ) ) ) |
18 |
16 17
|
sylbi |
|- ( -. y e. B -> ( B C_ ( suc x \ { y } ) <-> ( B \ { y } ) C_ ( suc x \ { y } ) ) ) |
19 |
13 18
|
syl5ibr |
|- ( -. y e. B -> ( B C_ suc x -> B C_ ( suc x \ { y } ) ) ) |
20 |
|
vex |
|- x e. _V |
21 |
20
|
sucex |
|- suc x e. _V |
22 |
21
|
difexi |
|- ( suc x \ { y } ) e. _V |
23 |
|
ssdomg |
|- ( ( suc x \ { y } ) e. _V -> ( B C_ ( suc x \ { y } ) -> B ~<_ ( suc x \ { y } ) ) ) |
24 |
22 23
|
ax-mp |
|- ( B C_ ( suc x \ { y } ) -> B ~<_ ( suc x \ { y } ) ) |
25 |
12 19 24
|
syl56 |
|- ( -. y e. B -> ( B C. suc x -> B ~<_ ( suc x \ { y } ) ) ) |
26 |
25
|
imp |
|- ( ( -. y e. B /\ B C. suc x ) -> B ~<_ ( suc x \ { y } ) ) |
27 |
|
vex |
|- y e. _V |
28 |
20 27
|
phplem3OLD |
|- ( ( x e. _om /\ y e. suc x ) -> x ~~ ( suc x \ { y } ) ) |
29 |
28
|
ensymd |
|- ( ( x e. _om /\ y e. suc x ) -> ( suc x \ { y } ) ~~ x ) |
30 |
|
domentr |
|- ( ( B ~<_ ( suc x \ { y } ) /\ ( suc x \ { y } ) ~~ x ) -> B ~<_ x ) |
31 |
26 29 30
|
syl2an |
|- ( ( ( -. y e. B /\ B C. suc x ) /\ ( x e. _om /\ y e. suc x ) ) -> B ~<_ x ) |
32 |
31
|
exp43 |
|- ( -. y e. B -> ( B C. suc x -> ( x e. _om -> ( y e. suc x -> B ~<_ x ) ) ) ) |
33 |
32
|
com4r |
|- ( y e. suc x -> ( -. y e. B -> ( B C. suc x -> ( x e. _om -> B ~<_ x ) ) ) ) |
34 |
33
|
imp |
|- ( ( y e. suc x /\ -. y e. B ) -> ( B C. suc x -> ( x e. _om -> B ~<_ x ) ) ) |
35 |
34
|
exlimiv |
|- ( E. y ( y e. suc x /\ -. y e. B ) -> ( B C. suc x -> ( x e. _om -> B ~<_ x ) ) ) |
36 |
11 35
|
mpcom |
|- ( B C. suc x -> ( x e. _om -> B ~<_ x ) ) |
37 |
|
endomtr |
|- ( ( suc x ~~ B /\ B ~<_ x ) -> suc x ~<_ x ) |
38 |
|
sssucid |
|- x C_ suc x |
39 |
|
ssdomg |
|- ( suc x e. _V -> ( x C_ suc x -> x ~<_ suc x ) ) |
40 |
21 38 39
|
mp2 |
|- x ~<_ suc x |
41 |
|
sbth |
|- ( ( suc x ~<_ x /\ x ~<_ suc x ) -> suc x ~~ x ) |
42 |
37 40 41
|
sylancl |
|- ( ( suc x ~~ B /\ B ~<_ x ) -> suc x ~~ x ) |
43 |
42
|
expcom |
|- ( B ~<_ x -> ( suc x ~~ B -> suc x ~~ x ) ) |
44 |
|
peano2b |
|- ( x e. _om <-> suc x e. _om ) |
45 |
|
nnord |
|- ( suc x e. _om -> Ord suc x ) |
46 |
44 45
|
sylbi |
|- ( x e. _om -> Ord suc x ) |
47 |
20
|
sucid |
|- x e. suc x |
48 |
|
nordeq |
|- ( ( Ord suc x /\ x e. suc x ) -> suc x =/= x ) |
49 |
46 47 48
|
sylancl |
|- ( x e. _om -> suc x =/= x ) |
50 |
|
nneneqOLD |
|- ( ( suc x e. _om /\ x e. _om ) -> ( suc x ~~ x <-> suc x = x ) ) |
51 |
44 50
|
sylanb |
|- ( ( x e. _om /\ x e. _om ) -> ( suc x ~~ x <-> suc x = x ) ) |
52 |
51
|
anidms |
|- ( x e. _om -> ( suc x ~~ x <-> suc x = x ) ) |
53 |
52
|
necon3bbid |
|- ( x e. _om -> ( -. suc x ~~ x <-> suc x =/= x ) ) |
54 |
49 53
|
mpbird |
|- ( x e. _om -> -. suc x ~~ x ) |
55 |
43 54
|
nsyli |
|- ( B ~<_ x -> ( x e. _om -> -. suc x ~~ B ) ) |
56 |
36 55
|
syli |
|- ( B C. suc x -> ( x e. _om -> -. suc x ~~ B ) ) |
57 |
56
|
com12 |
|- ( x e. _om -> ( B C. suc x -> -. suc x ~~ B ) ) |
58 |
|
psseq2 |
|- ( A = suc x -> ( B C. A <-> B C. suc x ) ) |
59 |
|
breq1 |
|- ( A = suc x -> ( A ~~ B <-> suc x ~~ B ) ) |
60 |
59
|
notbid |
|- ( A = suc x -> ( -. A ~~ B <-> -. suc x ~~ B ) ) |
61 |
58 60
|
imbi12d |
|- ( A = suc x -> ( ( B C. A -> -. A ~~ B ) <-> ( B C. suc x -> -. suc x ~~ B ) ) ) |
62 |
57 61
|
syl5ibrcom |
|- ( x e. _om -> ( A = suc x -> ( B C. A -> -. A ~~ B ) ) ) |
63 |
62
|
rexlimiv |
|- ( E. x e. _om A = suc x -> ( B C. A -> -. A ~~ B ) ) |
64 |
10 63
|
syl |
|- ( ( A e. _om /\ B C. A ) -> ( B C. A -> -. A ~~ B ) ) |
65 |
64
|
ex |
|- ( A e. _om -> ( B C. A -> ( B C. A -> -. A ~~ B ) ) ) |
66 |
65
|
pm2.43d |
|- ( A e. _om -> ( B C. A -> -. A ~~ B ) ) |
67 |
66
|
imp |
|- ( ( A e. _om /\ B C. A ) -> -. A ~~ B ) |