Theorem int2

Description: The virtual deduction introduction rule of converting the end virtual hypothesis of 2 virtual hypotheses into an antecedent. Conventional form of int2 is ex . (Contributed by Alan Sare, 23-Apr-2015) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	int2.1	|- (. (. ph ,. ps ). ->. ch ).
Assertion	int2	|- (. ph ->. ( ps -> ch ) ).

Proof

Step	Hyp	Ref	Expression
1		int2.1	|- (. (. ph ,. ps ). ->. ch ).
2	1	dfvd2ani	|- ( ( ph /\ ps ) -> ch )
3	2	ex	|- ( ph -> ( ps -> ch ) )
4	3	dfvd1ir	|- (. ph ->. ( ps -> ch ) ).