Step |
Hyp |
Ref |
Expression |
1 |
|
fofn |
|- ( F : A -onto-> B -> F Fn A ) |
2 |
1
|
3ad2ant3 |
|- ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) -> F Fn A ) |
3 |
|
forn |
|- ( F : A -onto-> B -> ran F = B ) |
4 |
|
eqimss2 |
|- ( ran F = B -> B C_ ran F ) |
5 |
3 4
|
syl |
|- ( F : A -onto-> B -> B C_ ran F ) |
6 |
5
|
3ad2ant3 |
|- ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) -> B C_ ran F ) |
7 |
|
simp2 |
|- ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) -> B e. Fin ) |
8 |
|
fipreima |
|- ( ( F Fn A /\ B C_ ran F /\ B e. Fin ) -> E. x e. ( ~P A i^i Fin ) ( F " x ) = B ) |
9 |
2 6 7 8
|
syl3anc |
|- ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) -> E. x e. ( ~P A i^i Fin ) ( F " x ) = B ) |
10 |
|
elinel2 |
|- ( x e. ( ~P A i^i Fin ) -> x e. Fin ) |
11 |
10
|
adantl |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> x e. Fin ) |
12 |
|
finnum |
|- ( x e. Fin -> x e. dom card ) |
13 |
11 12
|
syl |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> x e. dom card ) |
14 |
|
simpl3 |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> F : A -onto-> B ) |
15 |
|
fofun |
|- ( F : A -onto-> B -> Fun F ) |
16 |
14 15
|
syl |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> Fun F ) |
17 |
|
elinel1 |
|- ( x e. ( ~P A i^i Fin ) -> x e. ~P A ) |
18 |
17
|
elpwid |
|- ( x e. ( ~P A i^i Fin ) -> x C_ A ) |
19 |
18
|
adantl |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> x C_ A ) |
20 |
|
fof |
|- ( F : A -onto-> B -> F : A --> B ) |
21 |
|
fdm |
|- ( F : A --> B -> dom F = A ) |
22 |
14 20 21
|
3syl |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> dom F = A ) |
23 |
19 22
|
sseqtrrd |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> x C_ dom F ) |
24 |
|
fores |
|- ( ( Fun F /\ x C_ dom F ) -> ( F |` x ) : x -onto-> ( F " x ) ) |
25 |
16 23 24
|
syl2anc |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> ( F |` x ) : x -onto-> ( F " x ) ) |
26 |
|
fodomnum |
|- ( x e. dom card -> ( ( F |` x ) : x -onto-> ( F " x ) -> ( F " x ) ~<_ x ) ) |
27 |
13 25 26
|
sylc |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> ( F " x ) ~<_ x ) |
28 |
|
simpl1 |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> A e. V ) |
29 |
|
ssdomg |
|- ( A e. V -> ( x C_ A -> x ~<_ A ) ) |
30 |
28 19 29
|
sylc |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> x ~<_ A ) |
31 |
|
domtr |
|- ( ( ( F " x ) ~<_ x /\ x ~<_ A ) -> ( F " x ) ~<_ A ) |
32 |
27 30 31
|
syl2anc |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> ( F " x ) ~<_ A ) |
33 |
|
breq1 |
|- ( ( F " x ) = B -> ( ( F " x ) ~<_ A <-> B ~<_ A ) ) |
34 |
32 33
|
syl5ibcom |
|- ( ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) /\ x e. ( ~P A i^i Fin ) ) -> ( ( F " x ) = B -> B ~<_ A ) ) |
35 |
34
|
rexlimdva |
|- ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) -> ( E. x e. ( ~P A i^i Fin ) ( F " x ) = B -> B ~<_ A ) ) |
36 |
9 35
|
mpd |
|- ( ( A e. V /\ B e. Fin /\ F : A -onto-> B ) -> B ~<_ A ) |