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Theorem bj-cleqhyp 32892
Description: The hypothesis of bj-df-cleq 32893. Note that the hypothesis of bj-df-cleq 32893 actually has an additional dv condition on  x , 
y and therefore is provable by simply using ax-ext 2602 in place of axext3 2604 in the current proof. (Contributed by BJ, 24-Jun-2019.) (Proof modification is discouraged.)
Assertion
Ref Expression
bj-cleqhyp  |-  ( x  =  y  <->  A. z
( z  e.  x  <->  z  e.  y ) )
Distinct variable groups:    x, z    y, z

Proof of Theorem bj-cleqhyp
StepHypRef Expression
1 bj-elequ2g 32666 . 2  |-  ( x  =  y  ->  A. z
( z  e.  x  <->  z  e.  y ) )
2 axext3 2604 . 2  |-  ( A. z ( z  e.  x  <->  z  e.  y )  ->  x  =  y )
31, 2impbii 199 1  |-  ( x  =  y  <->  A. z
( z  e.  x  <->  z  e.  y ) )
Colors of variables: wff setvar class
Syntax hints:    <-> wb 196   A.wal 1481
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-ext 2602
This theorem depends on definitions:  df-bi 197  df-an 386  df-ex 1705
This theorem is referenced by:  bj-dfcleq  32894
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