Theorem pm5.74da

Description: Distribution of implication over biconditional (deduction form). Variant of pm5.74d . (Contributed by NM, 4-May-2007)

	Ref	Expression
Hypothesis	pm5.74da.1	|- ( ( ph /\ ps ) -> ( ch <-> th ) )
Assertion	pm5.74da	|- ( ph -> ( ( ps -> ch ) <-> ( ps -> th ) ) )

Proof

Step	Hyp	Ref	Expression
1		pm5.74da.1	|- ( ( ph /\ ps ) -> ( ch <-> th ) )
2	1	ex	|- ( ph -> ( ps -> ( ch <-> th ) ) )
3	2	pm5.74d	|- ( ph -> ( ( ps -> ch ) <-> ( ps -> th ) ) )