Metamath Proof Explorer


Theorem nfcsb1v

Description: Bound-variable hypothesis builder for substitution into a class. (Contributed by NM, 17-Aug-2006) (Revised by Mario Carneiro, 12-Oct-2016)

Ref Expression
Assertion nfcsb1v
|- F/_ x [_ A / x ]_ B

Proof

Step Hyp Ref Expression
1 nfcv
 |-  F/_ x A
2 1 nfcsb1
 |-  F/_ x [_ A / x ]_ B