Metamath Proof Explorer


Theorem ee221

Description: e221 without virtual deductions. (Contributed by Alan Sare, 13-Jul-2011) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypotheses ee221.1
|- ( ph -> ( ps -> ch ) )
ee221.2
|- ( ph -> ( ps -> th ) )
ee221.3
|- ( ph -> ta )
ee221.4
|- ( ch -> ( th -> ( ta -> et ) ) )
Assertion ee221
|- ( ph -> ( ps -> et ) )

Proof

Step Hyp Ref Expression
1 ee221.1
 |-  ( ph -> ( ps -> ch ) )
2 ee221.2
 |-  ( ph -> ( ps -> th ) )
3 ee221.3
 |-  ( ph -> ta )
4 ee221.4
 |-  ( ch -> ( th -> ( ta -> et ) ) )
5 3 a1d
 |-  ( ph -> ( ps -> ta ) )
6 1 2 5 4 ee222
 |-  ( ph -> ( ps -> et ) )