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Theorem bj-issetw 32860
Description: The closest one can get to isset 3207 without using ax-ext 2602. See also bj-vexw 32855. Note that the only dv condition is between  y and  A. (Contributed by BJ, 29-Apr-2019.) (Proof modification is discouraged.)
Hypothesis
Ref Expression
bj-issetw.1  |-  ph
Assertion
Ref Expression
bj-issetw  |-  ( A  e.  { x  | 
ph }  <->  E. y 
y  =  A )
Distinct variable group:    y, A
Allowed substitution hints:    ph( x, y)    A( x)

Proof of Theorem bj-issetw
StepHypRef Expression
1 bj-issetwt 32859 . 2  |-  ( A. x ph  ->  ( A  e.  { x  |  ph } 
<->  E. y  y  =  A ) )
2 bj-issetw.1 . 2  |-  ph
31, 2mpg 1724 1  |-  ( A  e.  { x  | 
ph }  <->  E. y 
y  =  A )
Colors of variables: wff setvar class
Syntax hints:    <-> wb 196    = wceq 1483   E.wex 1704    e. wcel 1990   {cab 2608
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-12 2047
This theorem depends on definitions:  df-bi 197  df-an 386  df-ex 1705  df-sb 1881  df-clab 2609  df-clel 2618
This theorem is referenced by: (None)
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