Theorem wl-luk-pm2.18d

Description: Deduction based on reductio ad absurdum. Copy of pm2.18d with a different proof. (Contributed by Wolf Lammen, 17-Dec-2018) (New usage is discouraged.) (Proof modification is discouraged.)

	Ref	Expression
Hypothesis	wl-luk-pm2.18d.1	⊢ ( 𝜑 → ( ¬ 𝜓 → 𝜓 ) )
Assertion	wl-luk-pm2.18d	⊢ ( 𝜑 → 𝜓 )

Proof

Step	Hyp	Ref	Expression
1		wl-luk-pm2.18d.1	⊢ ( 𝜑 → ( ¬ 𝜓 → 𝜓 ) )
2		ax-luk2	⊢ ( ( ¬ 𝜓 → 𝜓 ) → 𝜓 )
3	1 2	wl-luk-syl	⊢ ( 𝜑 → 𝜓 )