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Theorem nfreu1 2625
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 2439 . 2  |-  ( E! x  e.  A  ph  <->  E! x ( x  e.  A  /\  ph )
)
2 nfeu1 2014 . 2  |-  F/ x E! x ( x  e.  A  /\  ph )
31, 2nfxfr 1451 1  |-  F/ x E! x  e.  A  ph
Colors of variables: wff set class
Syntax hints:    /\ wa 103   F/wnf 1437   E!weu 2003    e. wcel 2125   E!wreu 2434
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-4 1487  ax-ial 1511
This theorem depends on definitions:  df-bi 116  df-nf 1438  df-eu 2006  df-reu 2439
This theorem is referenced by:  riota2df  5790
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