Metamath Proof Explorer


Theorem elfpw

Description: Membership in a class of finite subsets. (Contributed by Stefan O'Rear, 4-Apr-2015) (Revised by Mario Carneiro, 22-Aug-2015)

Ref Expression
Assertion elfpw A𝒫BFinABAFin

Proof

Step Hyp Ref Expression
1 elin A𝒫BFinA𝒫BAFin
2 elpwg AFinA𝒫BAB
3 2 pm5.32ri A𝒫BAFinABAFin
4 1 3 bitri A𝒫BFinABAFin