Theorem dfvd2ir

Description: Right-to-left inference form of dfvd2 . (Contributed by Alan Sare, 14-Nov-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	dfvd2ir.1	|- ( ph -> ( ps -> ch ) )
Assertion	dfvd2ir	|- (. ph ,. ps ->. ch ).

Proof

Step	Hyp	Ref	Expression
1		dfvd2ir.1	|- ( ph -> ( ps -> ch ) )
2		dfvd2	|- ( (. ph ,. ps ->. ch ). <-> ( ph -> ( ps -> ch ) ) )
3	1 2	mpbir	|- (. ph ,. ps ->. ch ).