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Theorem orbi1d 683
Description: Deduction adding a right disjunct to both sides of a logical equivalence. (Contributed by NM, 5-Aug-1993.)
Hypothesis
Ref Expression
bid.1
Assertion
Ref Expression
orbi1d

Proof of Theorem orbi1d
StepHypRef Expression
1 bid.1 . . 3
21orbi2d 682 . 2
3 orcom 376 . 2
4 orcom 376 . 2
52, 3, 43bitr4g 279 1
Colors of variables: wff setvar class
Syntax hints:   wi 4   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:  orbi1  686  orbi12d  690  eueq2  3010  uneq1  3411  r19.45zv  3647  rexprg  3776  rextpg  3778  lefinlteq  4463
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