fact: Fixpoint subtract {A: Type} (eq_dec : forall x y : A, {x = y} + {x <> y}) (l1 l2 : list A) : list A := match l2 with | nil => l1 | e :: l => subtract eq_dec (remove eq_dec e l1) l end.
imports: Coq.Lists.List Coq.micromega.Lia Coq.Sorting.Permutation Coq.ZArith.ZArith_base Coq.ZArith.Zcomplements Coq.Logic.FunctionalExtensionality CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext VST.zlist.sublist VST.zlist.list_solver