Theorem pm2.46 387

Description: Theorem *2.46 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.46	⊢ (¬ (φ ∨ ψ) → ¬ ψ)

Proof of Theorem pm2.46

Step	Hyp	Ref	Expression
1		olc 373	. 2 ⊢ (ψ → (φ ∨ ψ))
2	1	con3i 127	1 ⊢ (¬ (φ ∨ ψ) → ¬ ψ)

Syntax hints:  ¬ wn 3   → wi 4   ∨ wo 357

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 177  df-or 359

This theorem is referenced by:  pm2.48  389  pm2.49  390  rb-ax3  1519  eueq3  3012