Theorem imp4a

Description: An importation inference. (Contributed by NM, 26-Apr-1994) (Proof shortened by Wolf Lammen, 19-Jul-2021)

	Ref	Expression
Hypothesis	imp4.1	|- ( ph -> ( ps -> ( ch -> ( th -> ta ) ) ) )
Assertion	imp4a	|- ( ph -> ( ps -> ( ( ch /\ th ) -> ta ) ) )

Proof

Step	Hyp	Ref	Expression
1		imp4.1	|- ( ph -> ( ps -> ( ch -> ( th -> ta ) ) ) )
2	1	imp4b	|- ( ( ph /\ ps ) -> ( ( ch /\ th ) -> ta ) )
3	2	ex	|- ( ph -> ( ps -> ( ( ch /\ th ) -> ta ) ) )