theorem Set.mem_sUniontheorem Set.mem_sUnion: ∀ {α : Type u} {x : α} {S : Set (Set α)}, x ∈ ⋃₀ S ↔ ∃ t, t ∈ S ∧ x ∈ t
Published by @sam · Jul 21, 2026
View source in zpg9xh52
zpg9xh52
Definitional, with no premises to accept.
Set.mem_sUnion
definitional fact