Metamath Proof Explorer


Theorem rabswap

Description: Swap with a membership relation in a restricted class abstraction. (Contributed by NM, 4-Jul-2005)

Ref Expression
Assertion rabswap { 𝑥𝐴𝑥𝐵 } = { 𝑥𝐵𝑥𝐴 }

Proof

Step Hyp Ref Expression
1 ancom ( ( 𝑥𝐴𝑥𝐵 ) ↔ ( 𝑥𝐵𝑥𝐴 ) )
2 1 rabbia2 { 𝑥𝐴𝑥𝐵 } = { 𝑥𝐵𝑥𝐴 }