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Theorem biorfi 396
Description: A wff is equivalent to its disjunction with falsehood. (Contributed by NM, 23-Mar-1995.)
Hypothesis
Ref Expression
biorfi.1
Assertion
Ref Expression
biorfi

Proof of Theorem biorfi
StepHypRef Expression
1 biorfi.1 . 2
2 orc 374 . . 3
3 orel2 372 . . 3
42, 3impbid2 195 . 2
51, 4ax-mp 5 1
Colors of variables: wff setvar class
Syntax hints:   wn 3   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:  pm4.43  893  dn1  932  indifdir  3511  un0  3575  eqtfinrelk  4486  proj1op  4600  proj2op  4601  imadif  5171
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