Theorem exp516

Description: A triple exportation inference. (Contributed by Jeff Hankins, 8-Jul-2009)

	Ref	Expression
Hypothesis	exp516.1	|- ( ( ( ph /\ ( ps /\ ch /\ th ) ) /\ ta ) -> et )
Assertion	exp516	|- ( ph -> ( ps -> ( ch -> ( th -> ( ta -> et ) ) ) ) )

Proof

Step	Hyp	Ref	Expression
1		exp516.1	|- ( ( ( ph /\ ( ps /\ ch /\ th ) ) /\ ta ) -> et )
2	1	exp31	|- ( ph -> ( ( ps /\ ch /\ th ) -> ( ta -> et ) ) )
3	2	3expd	|- ( ph -> ( ps -> ( ch -> ( th -> ( ta -> et ) ) ) ) )