Type ↔ shape & behaviour of data to rep set of values
Class Range ↔ a set of characters express by hypen pattern: a-z
Superset ↔ extension to set (language extends base Programming Language)
Numeric Literal Type ↔ fixed set of specific values for number as Type
String Literal Type ↔ fixed set of specific values for string as types
Union Type ↔ Compound Type join by | Type Operator to define each member of Type set can EITHER be
bottom type ↔ empty Type set to match nothing but itself; never
Intersection Type ↔ Compound Type to merge via & Type Operator to express Type as being ALL of Type set