Metamath Proof Explorer


Theorem bnj1538

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Hypothesis bnj1538.1 𝐴 = { 𝑥𝐵𝜑 }
Assertion bnj1538 ( 𝑥𝐴𝜑 )

Proof

Step Hyp Ref Expression
1 bnj1538.1 𝐴 = { 𝑥𝐵𝜑 }
2 1 rabeq2i ( 𝑥𝐴 ↔ ( 𝑥𝐵𝜑 ) )
3 2 simprbi ( 𝑥𝐴𝜑 )