Notation "'foreach' '(' x 'in' ls ')' c " := (compMap _ (fun x => c) ls) (right associativity, at level 85, only parsing) : comp_scope.Notation "'for' '(' x ''<' n ')' c " := (map (fun x => c) (allNatsLt n)) (right associativity, at level 86, only parsing).

Lemma removePresent_not_in : forall (A : Set)(eqd : eq_dec A)(a : A) ls1 ls2, In a (removePresent eqd ls1 ls2) -> In a ls1 -> False.