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Theorem orordir 517
Description: Distribution of disjunction over disjunction. (Contributed by NM, 25-Feb-1995.)
Assertion
Ref Expression
orordir

Proof of Theorem orordir
StepHypRef Expression
1 oridm 500 . . 3
21orbi2i 505 . 2
3 or4 514 . 2
42, 3bitr3i 242 1
Colors of variables: wff setvar class
Syntax hints:   wb 176   wo 357
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  df-or 359
This theorem is referenced by:  sspsstri  3371
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