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Theorem bj-exexbiex 31255
Description: Adding a second quantifier is a tranparent operation, ( E. E. case). (Contributed by BJ, 20-Oct-2019.)
Assertion
Ref Expression
bj-exexbiex  |-  ( E. x E. x ph  <->  E. x ph )

Proof of Theorem bj-exexbiex
StepHypRef Expression
1 nfe1 1894 . 2  |-  F/ x E. x ph
2119.9 1947 1  |-  ( E. x E. x ph  <->  E. x ph )
Colors of variables: wff setvar class
Syntax hints:    <-> wb 187   E.wex 1657
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1663  ax-4 1676  ax-5 1752  ax-6 1798  ax-7 1843  ax-10 1891  ax-12 1909
This theorem depends on definitions:  df-bi 188  df-ex 1658  df-nf 1662
This theorem is referenced by: (None)
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