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Theorem 19.25 1676
Description: Theorem 19.25 of [Margaris] p. 90. (Contributed by NM, 12-Mar-1993.)
Assertion
Ref Expression
19.25  |-  ( A. y E. x ( ph  ->  ps )  ->  ( E. y A. x ph  ->  E. y E. x ps ) )

Proof of Theorem 19.25
StepHypRef Expression
1 19.35 1672 . . 3  |-  ( E. x ( ph  ->  ps )  <->  ( A. x ph  ->  E. x ps )
)
21biimpi 194 . 2  |-  ( E. x ( ph  ->  ps )  ->  ( A. x ph  ->  E. x ps ) )
32aleximi 1638 1  |-  ( A. y E. x ( ph  ->  ps )  ->  ( E. y A. x ph  ->  E. y E. x ps ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4   A.wal 1379   E.wex 1597
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1603  ax-4 1616
This theorem depends on definitions:  df-bi 185  df-ex 1598
This theorem is referenced by: (None)
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