Theorem pm2.62 210

Description: Theorem *2.62 of [WhiteheadRussell] p. 107.

Assertion

Ref	Expression
pm2.62	⊢ ((φ ∨ ψ) → ((φ → ψ) → ψ))

Proof of Theorem pm2.62

Step	Hyp	Ref	Expression
1		dfor2 199	. 2 ⊢ ((φ ∨ ψ) ↔ ((φ → ψ) → ψ))
2	1	biimp 133	1 ⊢ ((φ ∨ ψ) → ((φ → ψ) → ψ))

Syntax hints:   → wi 2   ∨ wo 195

This theorem is referenced by:  pm2.621 211

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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