Metamath Proof Explorer


Theorem rabbii

Description: Equivalent wff's correspond to equal restricted class abstractions. Inference form of rabbidv . (Contributed by Peter Mazsa, 1-Nov-2019)

Ref Expression
Hypothesis rabbii.1 ( 𝜑𝜓 )
Assertion rabbii { 𝑥𝐴𝜑 } = { 𝑥𝐴𝜓 }

Proof

Step Hyp Ref Expression
1 rabbii.1 ( 𝜑𝜓 )
2 1 a1i ( 𝑥𝐴 → ( 𝜑𝜓 ) )
3 2 rabbiia { 𝑥𝐴𝜑 } = { 𝑥𝐴𝜓 }