Theorem ee020

Description: e020 without virtual deductions. (Contributed by Alan Sare, 13-Jul-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypotheses	ee020.1	|- ph
	ee020.2	|- ( ps -> ( ch -> th ) )
	ee020.3	|- ta
	ee020.4	|- ( ph -> ( th -> ( ta -> et ) ) )
Assertion	ee020	|- ( ps -> ( ch -> et ) )

Proof

Step	Hyp	Ref	Expression
1		ee020.1	|- ph
2		ee020.2	|- ( ps -> ( ch -> th ) )
3		ee020.3	|- ta
4		ee020.4	|- ( ph -> ( th -> ( ta -> et ) ) )
5	1	a1i	|- ( ch -> ph )
6	5	a1i	|- ( ps -> ( ch -> ph ) )
7	3	a1i	|- ( ch -> ta )
8	7	a1i	|- ( ps -> ( ch -> ta ) )
9	6 2 8 4	ee222	|- ( ps -> ( ch -> et ) )