Theorem bilani

Description: Inference adding a conjunct to the left-hand side of a biconditional. (Contributed by Matthew House, 22-May-2026)

	Ref	Expression
Hypothesis	birani.1	⊢ ( 𝜑 ↔ 𝜓 )
Assertion	bilani	⊢ ( ( 𝜒 ∧ 𝜑 ) → 𝜓 )

Proof

Step	Hyp	Ref	Expression
1		birani.1	⊢ ( 𝜑 ↔ 𝜓 )
2	1	biimpi	⊢ ( 𝜑 → 𝜓 )
3	2	adantl	⊢ ( ( 𝜒 ∧ 𝜑 ) → 𝜓 )