MPE Home Metamath Proof Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >  con2bi Unicode version

Theorem con2bi 328
Description: Contraposition. Theorem *4.12 of [WhiteheadRussell] p. 117. (Contributed by NM, 15-Apr-1995.) (Proof shortened by Wolf Lammen, 3-Jan-2013.)
Assertion
Ref Expression
con2bi

Proof of Theorem con2bi
StepHypRef Expression
1 notbi 295 . 2
2 notnot 291 . . 3
32bibi2i 313 . 2
4 bicom 200 . 2
51, 3, 43bitr2i 273 1
Colors of variables: wff setvar class
Syntax hints:  -.wn 3  <->wb 184
This theorem is referenced by:  con2bid  329  nbbn  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 185
  Copyright terms: Public domain W3C validator