Metamath Proof Explorer

Theorem cbvreucsf

Description: A more general version of cbvreuv that has no distinct variable restrictions. Changes bound variables using implicit substitution. Usage of this theorem is discouraged because it depends on ax-13 . (Contributed by Andrew Salmon, 13-Jul-2011) (New usage is discouraged.)

Ref Expression
Hypotheses cbvralcsf.1 
|- F/_ y A
cbvralcsf.2 
|- F/_ x B
cbvralcsf.3 
|- F/ y ph
cbvralcsf.4 
|- F/ x ps
cbvralcsf.5 
|- ( x = y -> A = B )
cbvralcsf.6 
|- ( x = y -> ( ph <-> ps ) )
Assertion cbvreucsf 
|- ( E! x e. A ph <-> E! y e. B ps )

Proof

Step Hyp Ref Expression
1 cbvralcsf.1 
 |-  F/_ y A
2 cbvralcsf.2 
 |-  F/_ x B
3 cbvralcsf.3 
 |-  F/ y ph
4 cbvralcsf.4 
 |-  F/ x ps
5 cbvralcsf.5 
 |-  ( x = y -> A = B )
6 cbvralcsf.6 
 |-  ( x = y -> ( ph <-> ps ) )
7 nfv 
 |-  F/ z ( x e. A /\ ph )
8 nfcsb1v 
 |-  F/_ x [_ z / x ]_ A
9 8 nfcri 
 |-  F/ x z e. [_ z / x ]_ A
10 nfs1v 
 |-  F/ x [ z / x ] ph
11 9 10 nfan 
 |-  F/ x ( z e. [_ z / x ]_ A /\ [ z / x ] ph )
12 id 
 |-  ( x = z -> x = z )
13 csbeq1a 
 |-  ( x = z -> A = [_ z / x ]_ A )
14 12 13 eleq12d 
 |-  ( x = z -> ( x e. A <-> z e. [_ z / x ]_ A ) )
15 sbequ12 
 |-  ( x = z -> ( ph <-> [ z / x ] ph ) )
16 14 15 anbi12d 
 |-  ( x = z -> ( ( x e. A /\ ph ) <-> ( z e. [_ z / x ]_ A /\ [ z / x ] ph ) ) )
17 7 11 16 cbveu 
 |-  ( E! x ( x e. A /\ ph ) <-> E! z ( z e. [_ z / x ]_ A /\ [ z / x ] ph ) )
18 nfcv 
 |-  F/_ y z
19 18 1 nfcsb 
 |-  F/_ y [_ z / x ]_ A
20 19 nfcri 
 |-  F/ y z e. [_ z / x ]_ A
21 3 nfsb 
 |-  F/ y [ z / x ] ph
22 20 21 nfan 
 |-  F/ y ( z e. [_ z / x ]_ A /\ [ z / x ] ph )
23 nfv 
 |-  F/ z ( y e. B /\ ps )
24 id 
 |-  ( z = y -> z = y )
25 csbeq1 
 |-  ( z = y -> [_ z / x ]_ A = [_ y / x ]_ A )
26 sbsbc 
 |-  ( [ y / x ] v e. A <-> [. y / x ]. v e. A )
27 26 abbii 
 |-  { v | [ y / x ] v e. A } = { v | [. y / x ]. v e. A }
28 2 nfcri 
 |-  F/ x v e. B
29 5 eleq2d 
 |-  ( x = y -> ( v e. A <-> v e. B ) )
30 28 29 sbie 
 |-  ( [ y / x ] v e. A <-> v e. B )
31 30 bicomi 
 |-  ( v e. B <-> [ y / x ] v e. A )
32 31 abbi2i 
 |-  B = { v | [ y / x ] v e. A }
33 df-csb 
 |-  [_ y / x ]_ A = { v | [. y / x ]. v e. A }
34 27 32 33 3eqtr4ri 
 |-  [_ y / x ]_ A = B
35 25 34 eqtrdi 
 |-  ( z = y -> [_ z / x ]_ A = B )
36 24 35 eleq12d 
 |-  ( z = y -> ( z e. [_ z / x ]_ A <-> y e. B ) )
37 sbequ 
 |-  ( z = y -> ( [ z / x ] ph <-> [ y / x ] ph ) )
38 4 6 sbie 
 |-  ( [ y / x ] ph <-> ps )
39 37 38 bitrdi 
 |-  ( z = y -> ( [ z / x ] ph <-> ps ) )
40 36 39 anbi12d 
 |-  ( z = y -> ( ( z e. [_ z / x ]_ A /\ [ z / x ] ph ) <-> ( y e. B /\ ps ) ) )
41 22 23 40 cbveu 
 |-  ( E! z ( z e. [_ z / x ]_ A /\ [ z / x ] ph ) <-> E! y ( y e. B /\ ps ) )
42 17 41 bitri 
 |-  ( E! x ( x e. A /\ ph ) <-> E! y ( y e. B /\ ps ) )
43 df-reu 
 |-  ( E! x e. A ph <-> E! x ( x e. A /\ ph ) )
44 df-reu 
 |-  ( E! y e. B ps <-> E! y ( y e. B /\ ps ) )
45 42 43 44 3bitr4i 
 |-  ( E! x e. A ph <-> E! y e. B ps )