Theorem pm2.1 495

Description: Theorem *2.1 of [WhiteheadRussell] p. 101.

Assertion

Ref	Expression
pm2.1	⊢ (¬ φ ∨ φ)

Proof of Theorem pm2.1

Step	Hyp	Ref	Expression
1		nega 78	. 2 ⊢ (¬ ¬ φ → φ)
2	1	orri 201	1 ⊢ (¬ φ ∨ φ)

Syntax hints:  ¬ wn 1   ∨ wo 195

This theorem is referenced by:  hiidge0t 5056

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

This theorem depends on definitions:  df-bi 128  df-or 197

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