Theorem pm2.43d

Description: Deduction absorbing redundant antecedent. Deduction associated with pm2.43 and pm2.43i . (Contributed by NM, 18-Aug-1993) (Proof shortened by Mel L. O'Cat, 28-Nov-2008)

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

Proof

Step	Hyp	Ref	Expression
1		pm2.43d.1	⊢ ( 𝜑 → ( 𝜓 → ( 𝜓 → 𝜒 ) ) )
2		id	⊢ ( 𝜓 → 𝜓 )
3	2 1	mpdi	⊢ ( 𝜑 → ( 𝜓 → 𝜒 ) )