Theorem a1i

Description: Inference introducing an antecedent. Inference associated with ax-1 . Its associated inference is a1ii . See conventions for a definition of "associated inference". (Contributed by NM, 29-Dec-1992)

	Ref	Expression
Hypothesis	a1i.1	⊢ 𝜑
Assertion	a1i	⊢ ( 𝜓 → 𝜑 )

Proof

Step	Hyp	Ref	Expression
1		a1i.1	⊢ 𝜑
2		ax-1	⊢ ( 𝜑 → ( 𝜓 → 𝜑 ) )
3	1 2	ax-mp	⊢ ( 𝜓 → 𝜑 )