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Theorem 3orbi123d 1251
Description: Deduction joining 3 equivalences to form equivalence of disjunctions. (Contributed by NM, 20-Apr-1994.)
Hypotheses
Ref Expression
bi3d.1
bi3d.2
bi3d.3
Assertion
Ref Expression
3orbi123d

Proof of Theorem 3orbi123d
StepHypRef Expression
1 bi3d.1 . . . 4
2 bi3d.2 . . . 4
31, 2orbi12d 690 . . 3
4 bi3d.3 . . 3
53, 4orbi12d 690 . 2
6 df-3or 935 . 2
7 df-3or 935 . 2
85, 6, 73bitr4g 279 1
Colors of variables: wff setvar class
Syntax hints:   wi 4   wb 176   wo 357   w3o 933
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8
This theorem depends on definitions:  df-bi 177  df-or 359  df-3or 935
This theorem is referenced by:  moeq3  3013  ltfintri  4466  nncdiv3  6277
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