Theorem pm2.43b

Description: Inference absorbing redundant antecedent. (Contributed by NM, 31-Oct-1995)

	Ref	Expression
Hypothesis	pm2.43b.1	⊢ ( 𝜓 → ( 𝜑 → ( 𝜓 → 𝜒 ) ) )
Assertion	pm2.43b	⊢ ( 𝜑 → ( 𝜓 → 𝜒 ) )

Proof

Step	Hyp	Ref	Expression
1		pm2.43b.1	⊢ ( 𝜓 → ( 𝜑 → ( 𝜓 → 𝜒 ) ) )
2	1	pm2.43a	⊢ ( 𝜓 → ( 𝜑 → 𝜒 ) )
3	2	com12	⊢ ( 𝜑 → ( 𝜓 → 𝜒 ) )