ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  orbi1 Unicode version

Theorem orbi1 766
Description: Theorem *4.37 of [WhiteheadRussell] p. 118. (Contributed by NM, 3-Jan-2005.)
Assertion
Ref Expression
orbi1  |-  ( (
ph 
<->  ps )  ->  (
( ph  \/  ch ) 
<->  ( ps  \/  ch ) ) )

Proof of Theorem orbi1
StepHypRef Expression
1 id 19 . 2  |-  ( (
ph 
<->  ps )  ->  ( ph 
<->  ps ) )
21orbi1d 765 1  |-  ( (
ph 
<->  ps )  ->  (
( ph  \/  ch ) 
<->  ( ps  \/  ch ) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 104    \/ wo 682
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 683
This theorem depends on definitions:  df-bi 116
This theorem is referenced by:  prmdvdsexp  11753
  Copyright terms: Public domain W3C validator