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Metamath Proof Explorer

Theorem nfeq2

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

Ref Expression
Hypothesis nfeq2.1 ⊢ Ⅎ 𝑥 𝐵
Assertion nfeq2 Ⅎ 𝑥 𝐴 = 𝐵

Proof

Step Hyp Ref Expression
1 nfeq2.1 ⊢ Ⅎ 𝑥 𝐵
2 nfcv ⊢ Ⅎ 𝑥 𝐴
3 2 1 nfeq ⊢ Ⅎ 𝑥 𝐴 = 𝐵