Id.PredSourcePredicates over identifiers.
type elt = tThe type of the elements in the set.
val empty : tThe empty set.
val full : tThe set of all elements (of type elm).
val is_empty : t -> boolTest whether a set is empty or not.
val is_full : t -> boolTest whether a set contains the whole type or not.
add x s returns a set containing all elements of s, plus x. If x was already in s, then s is returned unchanged.
remove x s returns a set containing all elements of s, except x. If x was not in s, then s is returned unchanged.
equal s1 s2 tests whether the sets s1 and s2 are equal, that is, contain equal elements.