theorem IsChain.pairwiseDisjoint_iUnion₂ {α : Type u_1} {β : Type u_2} {c : Set (Set α)} (hc : IsChain (fun (x1 x2 : Set α) => x1 ⊆ x2) c) [PartialOrder β] [OrderBot β] (f : α → β) :
theorem IsChain.pairwiseDisjoint_sUnion {α : Type u_1} {β : Type u_2} {c : Set (Set α)} (hc : IsChain (fun (x1 x2 : Set α) => x1 ⊆ x2) c) [PartialOrder β] [OrderBot β] (f : α → β) :