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Theorem ianor 474
Description: Negated conjunction in terms of disjunction (De Morgan's law). Theorem *4.51 of [WhiteheadRussell] p. 120. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Andrew Salmon, 13-May-2011.)
Assertion
Ref Expression
ianor

Proof of Theorem ianor
StepHypRef Expression
1 imnan 411 . 2
2 pm4.62 408 . 2
31, 2bitr3i 242 1
Colors of variables: wff setvar class
Syntax hints:   wn 3   wi 4   wb 176   wo 357   wa 358
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360
This theorem is referenced by:  anor  475  3anor  948  cadnot  1394  19.33b  1608  neorian  2603  indifdir  3511  xpeq0  5046  imadif  5171  addceq0  6219
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