Theorem loolinALT 95

Description: The Linearity Axiom of the infinite-valued sentential logic (L-infinity) of Lukasiewicz. This version of loolin 173 does not use ax-3 8, meaning that this theorem is intuitionistically valid. (Contributed by O'Cat, 12-Aug-2004.) (New usage is discouraged.) (Proof modification is discouraged.)

Assertion

Ref	Expression
loolinALT	⊢ (((φ → ψ) → (ψ → φ)) → (ψ → φ))

Proof of Theorem loolinALT

Step	Hyp	Ref	Expression
1		jarr 91	. 2 ⊢ (((φ → ψ) → (ψ → φ)) → (ψ → (ψ → φ)))
2	1	pm2.43d 44	1 ⊢ (((φ → ψ) → (ψ → φ)) → (ψ → φ))

Syntax hints:   → wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7

This theorem is referenced by: (None)