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Theorem impbid21d 182
Description: Deduce an equivalence from two implications. (Contributed by Wolf Lammen, 12-May-2013.)
Hypotheses
Ref Expression
impbid21d.1
impbid21d.2
Assertion
Ref Expression
impbid21d

Proof of Theorem impbid21d
StepHypRef Expression
1 impbid21d.1 . . 3
21a1i 10 . 2
3 impbid21d.2 . . 3
43a1d 22 . 2
52, 4impbidd 181 1
Colors of variables: wff setvar class
Syntax hints:   wi 4   wb 176
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
This theorem is referenced by:  impbid  183  pm5.1im  229
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