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Theorem nfcii 2480
Description: Deduce that a class A does not have x free in it. (Contributed by Mario Carneiro, 11-Aug-2016.)
Ref Expression
nfcii.1 (y Ax y A)
Ref Expression
nfcii xA
Distinct variable groups:   x,y   y,A
Allowed substitution hint:   A(x)

Proof of Theorem nfcii
StepHypRef Expression
1 nfcii.1 . . 3 (y Ax y A)
21nfi 1551 . 2 x y A
32nfci 2479 1 xA
Colors of variables: wff setvar class
Syntax hints:  wi 4  wal 1540   wcel 1710  wnfc 2476
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546
This theorem depends on definitions:  df-bi 177  df-nf 1545  df-nfc 2478
This theorem is referenced by: (None)
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