Theorem e1bir

Description: Right biconditional form of e1a . sylibr is e1bir without virtual deductions. (Contributed by Alan Sare, 24-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypotheses	e1bir.1	⊢ (    𝜑    ▶    𝜓    )
	e1bir.2	⊢ ( 𝜒 ↔ 𝜓 )
Assertion	e1bir	⊢ (    𝜑    ▶    𝜒    )

Proof

Step	Hyp	Ref	Expression
1		e1bir.1	⊢ (    𝜑    ▶    𝜓    )
2		e1bir.2	⊢ ( 𝜒 ↔ 𝜓 )
3	2	biimpri	⊢ ( 𝜓 → 𝜒 )
4	1 3	e1a	⊢ (    𝜑    ▶    𝜒    )