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Theorem alinexa 1770
Description: A transformation of quantifiers and logical connectives. (Contributed by NM, 19-Aug-1993.)
Assertion
Ref Expression
alinexa (∀𝑥(𝜑 → ¬ 𝜓) ↔ ¬ ∃𝑥(𝜑𝜓))

Proof of Theorem alinexa
StepHypRef Expression
1 imnang 1769 . 2 (∀𝑥(𝜑 → ¬ 𝜓) ↔ ∀𝑥 ¬ (𝜑𝜓))
2 alnex 1706 . 2 (∀𝑥 ¬ (𝜑𝜓) ↔ ¬ ∃𝑥(𝜑𝜓))
31, 2bitri 264 1 (∀𝑥(𝜑 → ¬ 𝜓) ↔ ¬ ∃𝑥(𝜑𝜓))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 196  wa 384  wal 1481  wex 1704
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737
This theorem depends on definitions:  df-bi 197  df-an 386  df-ex 1705
This theorem is referenced by:  equs3  1875  ralnexOLD  2993  r2exlem  3059  zfregs2  8609  ac6n  9307  nnunb  11288  alexsubALTlem3  21853  nmobndseqi  27634  bj-exnalimn  32610  bj-ssbn  32641  frege124d  38053  zfregs2VD  39076
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