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Theorem nfcr 2247
Description: Consequence of the not-free predicate. (Contributed by Mario Carneiro, 11-Aug-2016.)
Assertion
Ref Expression
nfcr  |-  ( F/_ x A  ->  F/ x  y  e.  A )
Distinct variable groups:    x, y    y, A
Allowed substitution hint:    A( x)

Proof of Theorem nfcr
StepHypRef Expression
1 df-nfc 2244 . 2  |-  ( F/_ x A  <->  A. y F/ x  y  e.  A )
2 sp 1471 . 2  |-  ( A. y F/ x  y  e.  A  ->  F/ x  y  e.  A )
31, 2sylbi 120 1  |-  ( F/_ x A  ->  F/ x  y  e.  A )
Colors of variables: wff set class
Syntax hints:    -> wi 4   A.wal 1312   F/wnf 1419    e. wcel 1463   F/_wnfc 2242
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-4 1470
This theorem depends on definitions:  df-bi 116  df-nfc 2244
This theorem is referenced by:  nfcrii  2248  nfcrd  2269  abidnf  2821  csbtt  2981  csbnestgf  3018
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