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Metamath Proof Explorer

Theorem nfeq1

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

Ref Expression
Hypothesis nfeq1.1 
|- F/_ x A
Assertion nfeq1 
|- F/ x A = B

Proof

Step Hyp Ref Expression
1 nfeq1.1 
 |-  F/_ x A
2 nfcv 
 |-  F/_ x B
3 1 2 nfeq 
 |-  F/ x A = B