Theorem csbconstgf

Description: Substitution doesn't affect a constant B (in which x is not free). (Contributed by NM, 10-Nov-2005)

	Ref	Expression
Hypothesis	csbconstgf.1	|- F/_ x B
Assertion	csbconstgf	|- ( A e. V -> [_ A / x ]_ B = B )

Proof

Step	Hyp	Ref	Expression
1		csbconstgf.1	|- F/_ x B
2		csbtt	|- ( ( A e. V /\ F/_ x B ) -> [_ A / x ]_ B = B )
3	1 2	mpan2	|- ( A e. V -> [_ A / x ]_ B = B )