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Theorem hbe1 1891
Description:  x is not free in  E. x ph. (Contributed by NM, 24-Jan-1993.)
Assertion
Ref Expression
hbe1  |-  ( E. x ph  ->  A. x E. x ph )

Proof of Theorem hbe1
StepHypRef Expression
1 df-ex 1660 . 2  |-  ( E. x ph  <->  -.  A. x  -.  ph )
2 hbn1 1890 . 2  |-  ( -. 
A. x  -.  ph  ->  A. x  -.  A. x  -.  ph )
31, 2hbxfrbi 1690 1  |-  ( E. x ph  ->  A. x E. x ph )
Colors of variables: wff setvar class
Syntax hints:   -. wn 3    -> wi 4   A.wal 1435   E.wex 1659
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1665  ax-4 1678  ax-10 1889
This theorem depends on definitions:  df-bi 188  df-ex 1660
This theorem is referenced by:  nfe1  1892  hba1  1953  equs5e  2036  axie1  2401  ac6s6  32109  exlimexi  36508  vk15.4j  36512  vk15.4jVD  36941
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