Theorem pm3.13 317

Description: Theorem *3.13 of [WhiteheadRussell] p. 111.

Assertion

Ref	Expression
pm3.13	⊢ (¬ (φ ⋀ ψ) → (¬ φ ⋁ ¬ ψ))

Proof of Theorem pm3.13

Step	Hyp	Ref	Expression
1		pm3.11 315	. 2 ⊢ (¬ (¬ φ ⋁ ¬ ψ) → (φ ⋀ ψ))
2	1	con1i 96	1 ⊢ (¬ (φ ⋀ ψ) → (¬ φ ⋁ ¬ ψ))

Syntax hints:  ¬ wn 2   → wi 3   ⋁ wo 222   ⋀ wa 223

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-an 225

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