Theorem csbieOLD

Description: Obsolete version of csbie as of 15-Oct-2024. (Contributed by AV, 2-Dec-2019) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypotheses	csbieOLD.1	⊢ 𝐴 ∈ V
	csbieOLD.2	⊢ ( 𝑥 = 𝐴 → 𝐵 = 𝐶 )
Assertion	csbieOLD	⊢ ⦋ 𝐴 / 𝑥 ⦌ 𝐵 = 𝐶

Proof

Step	Hyp	Ref	Expression
1		csbieOLD.1	⊢ 𝐴 ∈ V
2		csbieOLD.2	⊢ ( 𝑥 = 𝐴 → 𝐵 = 𝐶 )
3		nfcv	⊢ Ⅎ 𝑥 𝐶
4	1 3 2	csbief	⊢ ⦋ 𝐴 / 𝑥 ⦌ 𝐵 = 𝐶