Theorem in3

Description: The virtual deduction introduction rule of converting the end virtual hypothesis of 3 virtual hypotheses into an antecedent. (Contributed by Alan Sare, 12-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	in3.1	|- (. ph ,. ps ,. ch ->. th ).
Assertion	in3	|- (. ph ,. ps ->. ( ch -> th ) ).

Proof

Step	Hyp	Ref	Expression
1		in3.1	|- (. ph ,. ps ,. ch ->. th ).
2	1	dfvd3i	|- ( ph -> ( ps -> ( ch -> th ) ) )
3	2	dfvd2ir	|- (. ph ,. ps ->. ( ch -> th ) ).