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Theorem rexbiiOLD 2942
Description: Obsolete proof of rexbii 2928 as of 6-Dec-2019. (Contributed by NM, 23-Nov-1994.) (Revised by Mario Carneiro, 17-Oct-2016.) (Proof modification is discouraged.) (New usage is discouraged.)
Hypothesis
Ref Expression
rexbiiOLD.1  |-  ( ph  <->  ps )
Assertion
Ref Expression
rexbiiOLD  |-  ( E. x  e.  A  ph  <->  E. x  e.  A  ps )

Proof of Theorem rexbiiOLD
StepHypRef Expression
1 rexbiiOLD.1 . . . 4  |-  ( ph  <->  ps )
21a1i 11 . . 3  |-  ( T. 
->  ( ph  <->  ps )
)
32rexbidv 2940 . 2  |-  ( T. 
->  ( E. x  e.  A  ph  <->  E. x  e.  A  ps )
)
43trud 1447 1  |-  ( E. x  e.  A  ph  <->  E. x  e.  A  ps )
Colors of variables: wff setvar class
Syntax hints:    <-> wb 188   T. wtru 1439   E.wrex 2777
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1666  ax-4 1679  ax-5 1749
This theorem depends on definitions:  df-bi 189  df-an 373  df-tru 1441  df-ex 1661  df-rex 2782
This theorem is referenced by: (None)
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