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Theorem zfauscl 3965
Description: Separation Scheme (Aussonderung) using a class variable. To derive this from ax-sep 3963, we invoke the Axiom of Extensionality (indirectly via vtocl 2674), which is needed for the justification of class variable notation. (Contributed by NM, 5-Aug-1993.)
Hypothesis
Ref Expression
zfauscl.1  |-  A  e. 
_V
Assertion
Ref Expression
zfauscl  |-  E. y A. x ( x  e.  y  <->  ( x  e.  A  /\  ph )
)
Distinct variable groups:    x, y, A    ph, y
Allowed substitution hint:    ph( x)

Proof of Theorem zfauscl
Dummy variable  z is distinct from all other variables.
StepHypRef Expression
1 zfauscl.1 . 2  |-  A  e. 
_V
2 eleq2 2152 . . . . . 6  |-  ( z  =  A  ->  (
x  e.  z  <->  x  e.  A ) )
32anbi1d 454 . . . . 5  |-  ( z  =  A  ->  (
( x  e.  z  /\  ph )  <->  ( x  e.  A  /\  ph )
) )
43bibi2d 231 . . . 4  |-  ( z  =  A  ->  (
( x  e.  y  <-> 
( x  e.  z  /\  ph ) )  <-> 
( x  e.  y  <-> 
( x  e.  A  /\  ph ) ) ) )
54albidv 1753 . . 3  |-  ( z  =  A  ->  ( A. x ( x  e.  y  <->  ( x  e.  z  /\  ph )
)  <->  A. x ( x  e.  y  <->  ( x  e.  A  /\  ph )
) ) )
65exbidv 1754 . 2  |-  ( z  =  A  ->  ( E. y A. x ( x  e.  y  <->  ( x  e.  z  /\  ph )
)  <->  E. y A. x
( x  e.  y  <-> 
( x  e.  A  /\  ph ) ) ) )
7 ax-sep 3963 . 2  |-  E. y A. x ( x  e.  y  <->  ( x  e.  z  /\  ph )
)
81, 6, 7vtocl 2674 1  |-  E. y A. x ( x  e.  y  <->  ( x  e.  A  /\  ph )
)
Colors of variables: wff set class
Syntax hints:    /\ wa 103    <-> wb 104   A.wal 1288    = wceq 1290   E.wex 1427    e. wcel 1439   _Vcvv 2620
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1382  ax-gen 1384  ax-ie1 1428  ax-ie2 1429  ax-8 1441  ax-4 1446  ax-17 1465  ax-i9 1469  ax-ial 1473  ax-ext 2071  ax-sep 3963
This theorem depends on definitions:  df-bi 116  df-nf 1396  df-sb 1694  df-clab 2076  df-cleq 2082  df-clel 2085  df-v 2622
This theorem is referenced by:  inex1  3979  bj-d0clsepcl  12093
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