Commit adc95f1c authored by Ralf Jung's avatar Ralf Jung
Browse files

Show equivalence of re-defined List.In and List.NoDup with Coq stdlib versions

parent 6ffa20c8
......@@ -933,10 +933,30 @@ Inductive elem_of_list {A} : ElemOf A (list A) :=
| elem_of_list_further (x y : A) l : x l x y :: l.
Existing Instance elem_of_list.
Lemma elem_of_list_In {A} (l : list A) x :
x l In x l.
Proof.
induction l.
- split; inversion 1.
- split; inversion 1; subst; (left + (right; apply IHl)); now auto.
Qed.
Inductive NoDup {A} : list A Prop :=
| NoDup_nil_2 : NoDup []
| NoDup_cons_2 x l : x l NoDup l NoDup (x :: l).
Lemma NoDup_ListNoDup {A} (l : list A) :
NoDup l List.NoDup l.
Proof.
induction l.
- split; intros _; now constructor.
- split; inversion 1; subst.
+ constructor; [now rewrite <-elem_of_list_In|].
now apply IHl.
+ constructor; [now rewrite elem_of_list_In|].
now apply IHl.
Qed.
(** Decidability of equality of the carrier set is admissible, but we add it
anyway so as to avoid cycles in type class search. *)
Class FinCollection A C `{ElemOf A C, Empty C, Singleton A C, Union C,
......
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