∀ {α : Type u_1} [inst : GeneralizedBooleanAlgebra α] [inst_1 : DecidableRel Disjoint] [inst_2 : DecidableLE α]
  [inst_3 : DecidableEq α] (u v : α) (s : Finset α),
  UV.compression u v s = {a ∈ s | UV.compress u v a ∈ s} ∪ {a ∈ Finset.image (UV.compress u v) s | a ∉ s}