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Theorem con4bii 297
Description: A contraposition inference. (Contributed by NM, 21-May-1994.)
Hypothesis
Ref Expression
con4bii.1
Assertion
Ref Expression
con4bii

Proof of Theorem con4bii
StepHypRef Expression
1 con4bii.1 . 2
2 notbi 295 . 2
31, 2mpbir 209 1
Colors of variables: wff setvar class
Syntax hints:  -.wn 3  <->wb 184
This theorem is referenced by:  2false  350  19.35OLD  1688  2ralor  3027  gencbval  3155  eq0  3800  snnzb  4094  raldifsnb  4161  uni0b  4274  tsna1  30551
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 185
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