Theorem 3mix2 818

Description: Introduction in triple disjunction.

Assertion

Ref	Expression
3mix2	⊢ (φ → (ψ ⋁ φ ⋁ χ))

Proof of Theorem 3mix2

Step	Hyp	Ref	Expression
1		3mix1 817	. 2 ⊢ (φ → (φ ⋁ χ ⋁ ψ))
2		3orrot 783	. 2 ⊢ ((ψ ⋁ φ ⋁ χ) ↔ (φ ⋁ χ ⋁ ψ))
3	1, 2	sylibr 200	1 ⊢ (φ → (ψ ⋁ φ ⋁ χ))

Syntax hints:   → wi 3   ⋁ w3o 776

This theorem is referenced by:  tz7.44-2 3935

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

This theorem depends on definitions:  df-bi 147  df-or 224  df-3or 778

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