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Theorem ceqsex4v 2997
Description: Elimination of four existential quantifiers, using implicit substitution. (Contributed by NM, 23-Sep-2011.)
Hypotheses
Ref Expression
ceqsex4v.1  |-  A  e. 
_V
ceqsex4v.2  |-  B  e. 
_V
ceqsex4v.3  |-  C  e. 
_V
ceqsex4v.4  |-  D  e. 
_V
ceqsex4v.7  |-  ( x  =  A  ->  ( ph 
<->  ps ) )
ceqsex4v.8  |-  ( y  =  B  ->  ( ps 
<->  ch ) )
ceqsex4v.9  |-  ( z  =  C  ->  ( ch 
<->  th ) )
ceqsex4v.10  |-  ( w  =  D  ->  ( th 
<->  ta ) )
Assertion
Ref Expression
ceqsex4v  |-  ( E. x E. y E. z E. w ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D )  /\  ph ) 
<->  ta )
Distinct variable groups:    x, y,
z, w, A    x, B, y, z, w    x, C, y, z, w    x, D, y, z, w    ps, x    ch, y    th, z    ta, w
Allowed substitution hints:    ph( x, y, z, w)    ps( y,
z, w)    ch( x, z, w)    th( x, y, w)    ta( x, y, z)

Proof of Theorem ceqsex4v
StepHypRef Expression
1 19.42vv 1931 . . . 4  |-  ( E. z E. w ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D  /\  ph )
)  <->  ( ( x  =  A  /\  y  =  B )  /\  E. z E. w ( z  =  C  /\  w  =  D  /\  ph )
) )
2 3anass 941 . . . . . 6  |-  ( ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D )  /\  ph ) 
<->  ( ( x  =  A  /\  y  =  B )  /\  (
( z  =  C  /\  w  =  D )  /\  ph )
) )
3 df-3an 939 . . . . . . 7  |-  ( ( z  =  C  /\  w  =  D  /\  ph )  <->  ( ( z  =  C  /\  w  =  D )  /\  ph ) )
43anbi2i 677 . . . . . 6  |-  ( ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D  /\  ph )
)  <->  ( ( x  =  A  /\  y  =  B )  /\  (
( z  =  C  /\  w  =  D )  /\  ph )
) )
52, 4bitr4i 245 . . . . 5  |-  ( ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D )  /\  ph ) 
<->  ( ( x  =  A  /\  y  =  B )  /\  (
z  =  C  /\  w  =  D  /\  ph ) ) )
652exbii 1594 . . . 4  |-  ( E. z E. w ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D )  /\  ph ) 
<->  E. z E. w
( ( x  =  A  /\  y  =  B )  /\  (
z  =  C  /\  w  =  D  /\  ph ) ) )
7 df-3an 939 . . . 4  |-  ( ( x  =  A  /\  y  =  B  /\  E. z E. w ( z  =  C  /\  w  =  D  /\  ph ) )  <->  ( (
x  =  A  /\  y  =  B )  /\  E. z E. w
( z  =  C  /\  w  =  D  /\  ph ) ) )
81, 6, 73bitr4i 270 . . 3  |-  ( E. z E. w ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D )  /\  ph ) 
<->  ( x  =  A  /\  y  =  B  /\  E. z E. w ( z  =  C  /\  w  =  D  /\  ph )
) )
982exbii 1594 . 2  |-  ( E. x E. y E. z E. w ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D )  /\  ph ) 
<->  E. x E. y
( x  =  A  /\  y  =  B  /\  E. z E. w ( z  =  C  /\  w  =  D  /\  ph )
) )
10 ceqsex4v.1 . . 3  |-  A  e. 
_V
11 ceqsex4v.2 . . 3  |-  B  e. 
_V
12 ceqsex4v.7 . . . . 5  |-  ( x  =  A  ->  ( ph 
<->  ps ) )
13123anbi3d 1261 . . . 4  |-  ( x  =  A  ->  (
( z  =  C  /\  w  =  D  /\  ph )  <->  ( z  =  C  /\  w  =  D  /\  ps )
) )
14132exbidv 1639 . . 3  |-  ( x  =  A  ->  ( E. z E. w ( z  =  C  /\  w  =  D  /\  ph )  <->  E. z E. w
( z  =  C  /\  w  =  D  /\  ps ) ) )
15 ceqsex4v.8 . . . . 5  |-  ( y  =  B  ->  ( ps 
<->  ch ) )
16153anbi3d 1261 . . . 4  |-  ( y  =  B  ->  (
( z  =  C  /\  w  =  D  /\  ps )  <->  ( z  =  C  /\  w  =  D  /\  ch )
) )
17162exbidv 1639 . . 3  |-  ( y  =  B  ->  ( E. z E. w ( z  =  C  /\  w  =  D  /\  ps )  <->  E. z E. w
( z  =  C  /\  w  =  D  /\  ch ) ) )
1810, 11, 14, 17ceqsex2v 2995 . 2  |-  ( E. x E. y ( x  =  A  /\  y  =  B  /\  E. z E. w ( z  =  C  /\  w  =  D  /\  ph ) )  <->  E. z E. w ( z  =  C  /\  w  =  D  /\  ch )
)
19 ceqsex4v.3 . . 3  |-  C  e. 
_V
20 ceqsex4v.4 . . 3  |-  D  e. 
_V
21 ceqsex4v.9 . . 3  |-  ( z  =  C  ->  ( ch 
<->  th ) )
22 ceqsex4v.10 . . 3  |-  ( w  =  D  ->  ( th 
<->  ta ) )
2319, 20, 21, 22ceqsex2v 2995 . 2  |-  ( E. z E. w ( z  =  C  /\  w  =  D  /\  ch )  <->  ta )
249, 18, 233bitri 264 1  |-  ( E. x E. y E. z E. w ( ( x  =  A  /\  y  =  B )  /\  ( z  =  C  /\  w  =  D )  /\  ph ) 
<->  ta )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 178    /\ wa 360    /\ w3a 937   E.wex 1551    = wceq 1653    e. wcel 1726   _Vcvv 2958
This theorem is referenced by:  ceqsex8v  2999  dihopelvalcpre  32108
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1556  ax-5 1567  ax-17 1627  ax-9 1667  ax-8 1688  ax-6 1745  ax-7 1750  ax-11 1762  ax-ext 2419
This theorem depends on definitions:  df-bi 179  df-an 362  df-3an 939  df-ex 1552  df-nf 1555  df-sb 1660  df-clab 2425  df-cleq 2431  df-clel 2434  df-v 2960
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