intros H; now rewrite H.
Qed.
#[local]
Hint Immediate InfA_ltA InfA_eqA : core.

(* Specifications: *)
Lemma SortA_InfA_InA :
forall l x a, SortA l -> InfA a l -> InA x l -> ltA a x.
Lemma In_InfA :
forall l x, (forall y, In y l -> ltA x y) -> InfA x l.
Lemma InA_InfA :
forall l x, (forall y, InA y l -> ltA x y) -> InfA x l.