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Theorem bj-nfcjust 34827
Description: Remove dependency on ax-ext 2432 (and df-cleq 2446 and ax-13 2004) from nfcjust 2603. (Contributed by BJ, 24-Jun-2019.) (Proof modification is discouraged.)
Assertion
Ref Expression
bj-nfcjust  |-  ( A. y F/ x  y  e.  A  <->  A. z F/ x  z  e.  A )
Distinct variable groups:    x, y,
z    y, A, z
Allowed substitution hint:    A( x)

Proof of Theorem bj-nfcjust
StepHypRef Expression
1 nfv 1712 . . 3  |-  F/ x  y  =  z
2 bj-eleq1w 34823 . . 3  |-  ( y  =  z  ->  (
y  e.  A  <->  z  e.  A ) )
31, 2nfbidf 1892 . 2  |-  ( y  =  z  ->  ( F/ x  y  e.  A 
<->  F/ x  z  e.  A ) )
43bj-cbvalvv 34699 1  |-  ( A. y F/ x  y  e.  A  <->  A. z F/ x  z  e.  A )
Colors of variables: wff setvar class
Syntax hints:    <-> wb 184   A.wal 1396   F/wnf 1621    e. wcel 1823
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1623  ax-4 1636  ax-5 1709  ax-6 1752  ax-7 1795  ax-10 1842  ax-11 1847  ax-12 1859
This theorem depends on definitions:  df-bi 185  df-an 369  df-ex 1618  df-nf 1622  df-clel 2449
This theorem is referenced by: (None)
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