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Theorem orbididc 860
 Description: Disjunction distributes over the biconditional, for a decidable proposition. Based on an axiom of system DS in Vladimir Lifschitz, "On calculational proofs" (1998), http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.25.3384. (Contributed by Jim Kingdon, 2-Apr-2018.)
Assertion
Ref Expression
orbididc DECID

Proof of Theorem orbididc
StepHypRef Expression
1 orimdidc 812 . . 3 DECID
2 orimdidc 812 . . 3 DECID
31, 2anbi12d 442 . 2 DECID
4 dfbi2 368 . . . 4
54orbi2i 679 . . 3
6 ordi 729 . . 3
75, 6bitri 173 . 2
8 dfbi2 368 . 2
93, 7, 83bitr4g 212 1 DECID
 Colors of variables: wff set class Syntax hints:   wi 4   wa 97   wb 98   wo 629  DECID wdc 742 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in2 545  ax-io 630 This theorem depends on definitions:  df-bi 110  df-dc 743 This theorem is referenced by:  pm5.7dc  861
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