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Theorem imnan 656
Description: Express implication in terms of conjunction. (Contributed by NM, 9-Apr-1994.) (Revised by Mario Carneiro, 1-Feb-2015.)
Assertion
Ref Expression
imnan ((𝜑 → ¬ 𝜓) ↔ ¬ (𝜑𝜓))

Proof of Theorem imnan
StepHypRef Expression
1 pm3.2im 598 . . . 4 (𝜑 → (𝜓 → ¬ (𝜑 → ¬ 𝜓)))
21imp 122 . . 3 ((𝜑𝜓) → ¬ (𝜑 → ¬ 𝜓))
32con2i 589 . 2 ((𝜑 → ¬ 𝜓) → ¬ (𝜑𝜓))
4 pm3.2 137 . . 3 (𝜑 → (𝜓 → (𝜑𝜓)))
54con3rr3 595 . 2 (¬ (𝜑𝜓) → (𝜑 → ¬ 𝜓))
63, 5impbii 124 1 ((𝜑 → ¬ 𝜓) ↔ ¬ (𝜑𝜓))
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 102  wb 103
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577
This theorem depends on definitions:  df-bi 115
This theorem is referenced by:  imnani  657  nan  658  pm3.24  659  imandc  819  ianordc  832  pm5.17dc  843  dn1dc  901  xorbin  1315  xordc1  1324  alinexa  1534  ralinexa  2393  rabeq0  3274  disj  3292  minel  3305  disjsn  3454  sotricim  4078  poirr2  4737  funun  4964  imadiflem  4998  imadif  4999  brprcneu  5191  prltlu  6677  caucvgprlemnbj  6857  caucvgprprlemnbj  6883  xrltnsym2  8869  fzp1nel  9121
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