Theorem e2bi

Description: Biconditional form of e2 . syl6ib is e2bi without virtual deductions. (Contributed by Alan Sare, 10-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypotheses	e2bi.1	|- (. ph ,. ps ->. ch ).
	e2bi.2	|- ( ch <-> th )
Assertion	e2bi	|- (. ph ,. ps ->. th ).

Proof

Step	Hyp	Ref	Expression
1		e2bi.1	|- (. ph ,. ps ->. ch ).
2		e2bi.2	|- ( ch <-> th )
3	2	biimpi	|- ( ch -> th )
4	1 3	e2	|- (. ph ,. ps ->. th ).