Metamath Proof Explorer


Theorem dfvd2imp

Description: The virtual deduction form of a 2-antecedent nested implication implies the 2-antecedent nested implication. (Contributed by Alan Sare, 21-Apr-2011) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion dfvd2imp
|- ( (. ph ,. ps ->. ch ). -> ( ph -> ( ps -> ch ) ) )

Proof

Step Hyp Ref Expression
1 dfvd2
 |-  ( (. ph ,. ps ->. ch ). <-> ( ph -> ( ps -> ch ) ) )
2 1 biimpi
 |-  ( (. ph ,. ps ->. ch ). -> ( ph -> ( ps -> ch ) ) )