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Theorem nf2 1866
Description: An alternative definition of df-nf 1545, which does not involve nested quantifiers on the same variable. (Contributed by Mario Carneiro, 24-Sep-2016.)
Assertion
Ref Expression
nf2  F/

Proof of Theorem nf2
StepHypRef Expression
1 df-nf 1545 . 2  F/
2 nfa1 1788 . . 3  F/
3219.23 1801 . 2
41, 3bitri 240 1  F/
Colors of variables: wff setvar class
Syntax hints:   wi 4   wb 176  wal 1540  wex 1541   F/wnf 1544
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-11 1746
This theorem depends on definitions:  df-bi 177  df-ex 1542  df-nf 1545
This theorem is referenced by:  nf3  1867  nf4  1868
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