An attribute-value system is a basic knowledge representation framework comprising a table with columns designating "attributes" (also known as "properties", "predicates," "features," "dimensions," "characteristics", "fields", "headers" or "independent variables" depending on the context) and "rows" designating "objects" (also known as "entities," "instances," "exemplars," "elements", "records" or "dependent variables"). Each table cell therefore designates the value (also known as "state") of a particular attribute of a particular object.