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Theorem orddi 721
Description: Double distributive law for disjunction. (Contributed by NM, 12-Aug-1994.)
Assertion
Ref Expression
orddi (((φ ψ) (χ θ)) ↔ (((φ χ) (φ θ)) ((ψ χ) (ψ θ))))

Proof of Theorem orddi
StepHypRef Expression
1 ordir 718 . 2 (((φ ψ) (χ θ)) ↔ ((φ (χ θ)) (ψ (χ θ))))
2 ordi 717 . . 3 ((φ (χ θ)) ↔ ((φ χ) (φ θ)))
3 ordi 717 . . 3 ((ψ (χ θ)) ↔ ((ψ χ) (ψ θ)))
42, 3anbi12i 436 . 2 (((φ (χ θ)) (ψ (χ θ))) ↔ (((φ χ) (φ θ)) ((ψ χ) (ψ θ))))
51, 4bitri 173 1 (((φ ψ) (χ θ)) ↔ (((φ χ) (φ θ)) ((ψ χ) (ψ θ))))
Colors of variables: wff set class
Syntax hints:   wa 97  wb 98   wo 616
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 617
This theorem depends on definitions:  df-bi 110
This theorem is referenced by:  prneimg  3515
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