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Theorem anor 475
Description: Conjunction in terms of disjunction (De Morgan's law). Theorem *4.5 of [WhiteheadRussell] p. 120. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Wolf Lammen, 3-Nov-2012.)
Assertion
Ref Expression
anor

Proof of Theorem anor
StepHypRef Expression
1 ianor 474 . . 3
21bicomi 193 . 2
32con2bii 322 1
Colors of variables: wff setvar class
Syntax hints:   wn 3   wb 176   wo 357   wa 358
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360
This theorem is referenced by:  pm3.1  484  pm3.11  485  dn1  932  3anor  948  ltcirr  6272
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