Theorem pm2.621 211

Description: Theorem *2.621 of [WhiteheadRussell] p. 107.

Assertion

Ref	Expression
pm2.621	⊢ ((φ → ψ) → ((φ ∨ ψ) → ψ))

Proof of Theorem pm2.621

Step	Hyp	Ref	Expression
1		pm2.62 210	. 2 ⊢ ((φ ∨ ψ) → ((φ → ψ) → ψ))
2	1	com12 13	1 ⊢ ((φ → ψ) → ((φ ∨ ψ) → ψ))

Syntax hints:   → wi 2   ∨ wo 195

This theorem is referenced by:  pm4.72 485

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

metamath.org