fact: Definition prefixes (a : A) : list A := isort (proj1_sig (constructive_indefinite_description _ (partial_order_included_in_total_order PO))) (undup (filterP (fun x => r x a) (proj1_sig (constructive_indefinite_description _ (F a))))).
imports: Arith micromega.Lia Setoid IndefiniteDescription ClassicalChoice HahnBase HahnList HahnEquational HahnRewrite HahnRelationsBasic HahnSets HahnNatExtra HahnListBefore HahnWf HahnSorted HahnTotalExt