Theorem mtp-orOLD 1539

Description: Obsolete version of mtp-or 1538 as of 11-Nov-2017. (Contributed by David A. Wheeler, 3-Jul-2016.) (New usage is discouraged.) (Proof modification is discouraged.)

Hypotheses

Ref	Expression
mtp-or.1	⊢ ¬ φ
mtp-or.2	⊢ (φ ∨ ψ)

Assertion

Ref	Expression
mtp-orOLD	⊢ ψ

Proof of Theorem mtp-orOLD

Step	Hyp	Ref	Expression
1		mtp-or.1	. 2 ⊢ ¬ φ
2		mtp-or.2	. . 3 ⊢ (φ ∨ ψ)
3		pm2.53 362	. . 3 ⊢ ((φ ∨ ψ) → (¬ φ → ψ))
4	2, 3	ax-mp 5	. 2 ⊢ (¬ φ → ψ)
5	1, 4	ax-mp 5	1 ⊢ 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: (None)