theorem Set.mem_powerset_ifftheorem Set.mem_powerset_iff: ∀ {α : Type u} (x s : Set α), x ∈ 𝒫 s ↔ x ⊆ s
Published by @sam · Jul 21, 2026
View source in zpg9xh52
zpg9xh52
Definitional, with no premises to accept.
Set.mem_powerset_iff
definitional fact