fact: Fixpoint getUnique(A : Set)(ls : list A)(pf : eq_dec A) : list A := match ls with | nil => nil | a :: ls' => let ls'' := (getUnique ls' pf) in if (in_dec pf a ls'') then ls'' else a :: ls'' end.
imports: FCF.Rat List Permutation Arith FCF.EqDec FCF.StdNat Bool Permutation