Subset and Superset

Beyond combining sets, you often need to check if one set is contained within another. These containment relationships are called subset and superset. A subset is a set where every element exists in another larger set. A superset is the opposite: it contains all elements of a smaller set plus possibly more. Subset and superset checks are fundamental for validation, permission checking, and hierarchical data. For example, checking if a user has required permissions (user permissions should be a superset of required permissions), or validating that input is within allowed values (input should be a subset of allowed values). The permission sets form a hierarchy: basic is a subset of editor, which is a subset of admin. This reflects the real permission structure where higher roles include all