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Theorem intnand 873
Description: Introduction of conjunct inside of a contradiction. (Contributed by NM, 10-Jul-2005.)
Hypothesis
Ref Expression
intnand.1 (𝜑 → ¬ 𝜓)
Assertion
Ref Expression
intnand (𝜑 → ¬ (𝜒𝜓))

Proof of Theorem intnand
StepHypRef Expression
1 intnand.1 . 2 (𝜑 → ¬ 𝜓)
2 simpr 108 . 2 ((𝜒𝜓) → 𝜓)
31, 2nsyl 590 1 (𝜑 → ¬ (𝜒𝜓))
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 102
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia2 105  ax-in1 576  ax-in2 577
This theorem is referenced by:  dcan  875  poxp  5873  cauappcvgprlemladdrl  6847  caucvgprlemladdrl  6868  xrrebnd  8886  fzpreddisj  9088  fzp1nel  9121  gcdsupex  10349  gcdsupcl  10350  gcdnncl  10359  gcd2n0cl  10361  qredeu  10479  cncongr2  10486
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