Theorem en2d 6827

Description: Equinumerosity inference from an implicit one-to-one onto function. (Contributed by NM, 27-Jul-2004.) (Revised by Mario Carneiro, 12-May-2014.)

Hypotheses

Ref	Expression
en2d.1	|- ( ph -> A e. _V )
en2d.2	|- ( ph -> B e. _V )
en2d.3	|- ( ph -> ( x e. A -> C e. _V ) )
en2d.4	|- ( ph -> ( y e. B -> D e. _V ) )
en2d.5	|- ( ph -> ( ( x e. A /\ y = C ) <-> ( y e. B /\ x = D ) ) )

Assertion

Ref	Expression
en2d	|- ( ph -> A ~~ B )

Distinct variable groups:   x, y, A   x, B, y   y, C   x, D   ph, x, y

Allowed substitution hints:   C( x)   D( y)

Proof of Theorem en2d

Step	Hyp	Ref	Expression
1		en2d.1	. 2 |- ( ph -> A e. _V )
2		en2d.2	. 2 |- ( ph -> B e. _V )
3		eqid 2196	. . 3 |- ( x e. A |-> C ) = ( x e. A |-> C )
4		en2d.3	. . . 4 |- ( ph -> ( x e. A -> C e. _V ) )
5	4	imp 124	. . 3 |- ( ( ph /\ x e. A ) -> C e. _V )
6		en2d.4	. . . 4 |- ( ph -> ( y e. B -> D e. _V ) )
7	6	imp 124	. . 3 |- ( ( ph /\ y e. B ) -> D e. _V )
8		en2d.5	. . 3 |- ( ph -> ( ( x e. A /\ y = C ) <-> ( y e. B /\ x = D ) ) )
9	3, 5, 7, 8	f1od 6126	. 2 |- ( ph -> ( x e. A |-> C ) : A -1-1-onto-> B )
10		f1oen2g 6814	. 2 |- ( ( A e. _V /\ B e. _V /\ ( x e. A |-> C ) : A -1-1-onto-> B ) -> A ~~ B )
11	1, 2, 9, 10	syl3anc 1249	1 |- ( ph -> A ~~ B )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   = wceq 1364   e. wcel 2167   _Vcvv 2763   class class class wbr 4033   |-> cmpt 4094   -1-1-onto->wf1o 5257   ~~ cen 6797

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 710  ax-5 1461  ax-7 1462  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-8 1518  ax-10 1519  ax-11 1520  ax-i12 1521  ax-bndl 1523  ax-4 1524  ax-17 1540  ax-i9 1544  ax-ial 1548  ax-i5r 1549  ax-13 2169  ax-14 2170  ax-ext 2178  ax-sep 4151  ax-pow 4207  ax-pr 4242  ax-un 4468

This theorem depends on definitions:  df-bi 117  df-3an 982  df-tru 1367  df-nf 1475  df-sb 1777  df-eu 2048  df-mo 2049  df-clab 2183  df-cleq 2189  df-clel 2192  df-nfc 2328  df-ral 2480  df-rex 2481  df-v 2765  df-un 3161  df-in 3163  df-ss 3170  df-pw 3607  df-sn 3628  df-pr 3629  df-op 3631  df-uni 3840  df-br 4034  df-opab 4095  df-mpt 4096  df-id 4328  df-xp 4669  df-rel 4670  df-cnv 4671  df-co 4672  df-dm 4673  df-rn 4674  df-fun 5260  df-fn 5261  df-f 5262  df-f1 5263  df-fo 5264  df-f1o 5265  df-en 6800

This theorem is referenced by:  en2i  6829  map1  6871