Metamath Proof Explorer

Theorem nfel2

Description: Hypothesis builder for elementhood, special case. (Contributed by Mario Carneiro, 10-Oct-2016)

Ref Expression
Hypothesis nfeq2.1 
|- F/_ x B
Assertion nfel2 
|- F/ x A e. B

Proof

Step Hyp Ref Expression
1 nfeq2.1 
 |-  F/_ x B
2 nfcv 
 |-  F/_ x A
3 2 1 nfel 
 |-  F/ x A e. B