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Theorem nfan1 2242
Description: A closed form of nfan 1926. (Contributed by Mario Carneiro, 3-Oct-2016.) df-nf 1811 changed. (Revised by Wolf Lammen, 18-Sep-2021.) (Proof shortened by Wolf Lammen, 7-Jul-2022.)
Hypotheses
Ref Expression
nfim1.1 𝑥𝜑
nfim1.2 (𝜑 → Ⅎ𝑥𝜓)
Assertion
Ref Expression
nfan1 𝑥(𝜑𝜓)

Proof of Theorem nfan1
StepHypRef Expression
1 df-an 401 . 2 ((𝜑𝜓) ↔ ¬ (𝜑 → ¬ 𝜓))
2 nfim1.1 . . . 4 𝑥𝜑
3 nfim1.2 . . . . 5 (𝜑 → Ⅎ𝑥𝜓)
43nfnd 1885 . . . 4 (𝜑 → Ⅎ𝑥 ¬ 𝜓)
52, 4nfim1 2241 . . 3 𝑥(𝜑 → ¬ 𝜓)
65nfn 1884 . 2 𝑥 ¬ (𝜑 → ¬ 𝜓)
71, 6nfxfr 1880 1 𝑥(𝜑𝜓)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wa 400  wnf 1810
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-12 2219
This theorem depends on definitions:  df-bi 210  df-an 401  df-or 861  df-ex 1807  df-nf 1811
This theorem is referenced by:  sb4b  2513  ralcom2  3372  sbcralt  3832  sbcrext  3833  csbiebt  3888  riota5f  7396  axrepndlem1  10577  axrepndlem2  10578  axunnd  10581  axpowndlem2  10583  axpowndlem3  10584  axpowndlem4  10585  axregndlem2  10588  axinfndlem1  10590  axinfnd  10591  axacndlem4  10595  axacndlem5  10596  axacnd  10597  fproddivf  16041  nfan1c  35406  axtcond  36912  mh-setindnd  36971  wl-sbcom2d-lem1  38137  wl-mo2df  38148  wl-eudf  38150  wl-mo3t  38154
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