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Theorem ordir 766
Description: Distributive law for disjunction. (Contributed by NM, 12-Aug-1994.)
Assertion
Ref Expression
ordir  |-  ( ( ( ph  /\  ps )  \/  ch )  <->  ( ( ph  \/  ch )  /\  ( ps  \/  ch ) ) )

Proof of Theorem ordir
StepHypRef Expression
1 ordi 765 . 2  |-  ( ( ch  \/  ( ph  /\ 
ps ) )  <->  ( ( ch  \/  ph )  /\  ( ch  \/  ps ) ) )
2 orcom 682 . 2  |-  ( ( ( ph  /\  ps )  \/  ch )  <->  ( ch  \/  ( ph  /\ 
ps ) ) )
3 orcom 682 . . 3  |-  ( (
ph  \/  ch )  <->  ( ch  \/  ph )
)
4 orcom 682 . . 3  |-  ( ( ps  \/  ch )  <->  ( ch  \/  ps )
)
53, 4anbi12i 448 . 2  |-  ( ( ( ph  \/  ch )  /\  ( ps  \/  ch ) )  <->  ( ( ch  \/  ph )  /\  ( ch  \/  ps ) ) )
61, 2, 53bitr4i 210 1  |-  ( ( ( ph  /\  ps )  \/  ch )  <->  ( ( ph  \/  ch )  /\  ( ps  \/  ch ) ) )
Colors of variables: wff set class
Syntax hints:    /\ wa 102    <-> wb 103    \/ wo 664
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 665
This theorem depends on definitions:  df-bi 115
This theorem is referenced by:  orddi  769  pm5.62dc  891  dn1dc  906  suc11g  4371  bj-peano4  11733
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