Metamath Proof Explorer


Theorem bnj1436

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

Ref Expression
Hypothesis bnj1436.1 𝐴 = { 𝑥𝜑 }
Assertion bnj1436 ( 𝑥𝐴𝜑 )

Proof

Step Hyp Ref Expression
1 bnj1436.1 𝐴 = { 𝑥𝜑 }
2 1 abeq2i ( 𝑥𝐴𝜑 )
3 2 biimpi ( 𝑥𝐴𝜑 )