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Theorem orabs 895
Description: Absorption of redundant internal disjunct. Compare Theorem *4.45 of [WhiteheadRussell] p. 119. (Contributed by NM, 21-Jun-1993.) (Proof shortened by Wolf Lammen, 28-Feb-2014.)
Assertion
Ref Expression
orabs (𝜑 ↔ ((𝜑𝜓) ∧ 𝜑))

Proof of Theorem orabs
StepHypRef Expression
1 orc 398 . 2 (𝜑 → (𝜑𝜓))
21pm4.71ri 662 1 (𝜑 ↔ ((𝜑𝜓) ∧ 𝜑))
Colors of variables: wff setvar class
Syntax hints:  wb 194  wo 381  wa 382
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 195  df-or 383  df-an 384
This theorem is referenced by: (None)
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