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Theorem con34b 283
Description: Contraposition. Theorem *4.1 of [WhiteheadRussell] p. 116. (Contributed by NM, 5-Aug-1993.)
Assertion
Ref Expression
con34b

Proof of Theorem con34b
StepHypRef Expression
1 con3 126 . 2
2 ax-3 8 . 2
31, 2impbii 180 1
Colors of variables: wff setvar class
Syntax hints:   wn 3   wi 4   wb 176
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
This theorem is referenced by:  mtt  329  pm4.14  561  sscon34  3661  evenodddisjlem1  4515
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