Types

Types are tied to topics. The types that have been applied to a topic determine the properties that topic will have. For instance, Martin Scorsese (which is a topic) is tied to the Person type. That means his properties will include Birthplace, Birth date, Parents, and so forth. Because Martin Scorsese is also typed as a Film director, the topic about him includes properties associated with that type, including Films Directed and Awards won.

Types generally have complementary, rather than overlapping, properties. So the Film director type holds properties that are relevant to film directing, but doesn't include properties related to being a person. 

• A type instance is a topic of a particular type. For example, Blade Runner is an instance of the type Film.
• A type definition (or schema) is the collection of properties that belong to a type.
• An expected type is associated with each property. That is, every property specifies what type of topic must appear in it. For instance, the Recording Artist type has a property Genre, which wants to be filled in with topics that are typed as Musical Genre.
• A compound value type (or CVT) is an element that ties together properties from several types. Typically (and trickily) a compound value type doesn't have a display name because it is only a container object for a group of properties. For example, the CVT "musical group membership" contains the name of a band, the name of the musician and the role or instrument played. This data will appear on the related topic instances of musical artist even though the properties exists within the compound value type. This is because musical group membership is a CVT and is the expected type for a property (members) on musical artist.