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Theorem nfreu1 2822
Description:  x is not free in  E! x  e.  A ph. (Contributed by NM, 19-Mar-1997.)
Assertion
Ref Expression
nfreu1  |-  F/ x E! x  e.  A  ph

Proof of Theorem nfreu1
StepHypRef Expression
1 df-reu 2657 . 2  |-  ( E! x  e.  A  ph  <->  E! x ( x  e.  A  /\  ph )
)
2 nfeu1 2249 . 2  |-  F/ x E! x ( x  e.  A  /\  ph )
31, 2nfxfr 1576 1  |-  F/ x E! x  e.  A  ph
Colors of variables: wff set class
Syntax hints:    /\ wa 359   F/wnf 1550    e. wcel 1717   E!weu 2239   E!wreu 2652
This theorem is referenced by:  nfriota1  6494  riota2df  6507  2reu8  27639
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1552  ax-5 1563  ax-17 1623  ax-9 1661  ax-8 1682  ax-6 1736  ax-7 1741  ax-11 1753
This theorem depends on definitions:  df-bi 178  df-ex 1548  df-nf 1551  df-eu 2243  df-reu 2657
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