class (Class)

Classes differ from Sets in two important respects. First, Classes are not assumed to be extensional. That is, distinct Classes might well have exactly the same instances. Second, Classes typically have an associated `condition' that determines the instances of the Class. So, for example, the condition `human' determines the Class of Humans. Note that some Classes might satisfy their own condition (e.g., the Class of Abstract things is Abstract) and hence be instances of themselves.

Ontology

SUMO / BASE-ONTOLOGY

Superclass(es)

entity

abstract

set or class

class

Instance(s)

inheritable relation

Coordinate term(s)

mutually disjoint class pairwise disjoint class set

Constrains relations

abstraction fn extension fn disjoint decomposition exhaustive decomposition partition

Related WordNet synsets

category: a general concept that marks divisions or coordinations in a conceptual scheme
kind, sort, form, variety: a category of things distinguished by some common characteristic or quality; "sculpture is a form of art"; "what kinds of desserts are there?"
classification, categorization: a group of people or things arranged by class or category
class, category, family: a collection of things sharing a common attribute; "there are two classes of detergents"
stamp: a type or class; "more men of his stamp are needed"

See more related synsets on a separate page.

Axioms (4)

if is covered by ,
then if element is a member of "()", then element is an instance of class

(=>
      (exhaustiveDecomposition @ROW)
      (=>
            (inList
                  ?ELEMENT
                  (ListFn @ROW))
            (instance ?ELEMENT Class)))

if is disjointly decomposed into ,
then if element is a member of "()", then element is an instance of class

(=>
      (disjointDecomposition @ROW)
      (=>
            (inList
                  ?ELEMENT
                  (ListFn @ROW))
            (instance ?ELEMENT Class)))

If class is an instance of class, then class is a subclass of entity.

(=>
      (instance ?CLASS Class)
      (subclass ?CLASS Entity))

set or class is exhaustively partitioned into set,class.

(partition SetOrClass Set Class)