∀ {α : Type u_2} {ε : Type u_1} [inst : Preorder α] (a : Thunk α) [inst_1 : Estimator a ε]
  [inst_2 : WellFoundedGT ↑(Set.range (EstimatorData.bound a))] (e : ε) (r : Bool) (e' : ε),
  (match some e' with
    | none => EstimatorData.bound a e = a.get
    | some e' => EstimatorData.bound a e < EstimatorData.bound a e') →
    (invImage (fun x => PSigma.casesOn x fun e r => ⟨EstimatorData.bound a e, ⋯⟩) WellFoundedGT.toWellFoundedRelation).1
      ⟨e', true⟩ ⟨e, r⟩