sowa#abstract__abstract_entity  distinguished from sumo#abstract because John Sowa does not seem to categorize all types of relations, sets, classes, attributes, quantities and graphs under this category; see http://www.jfsowa.com/ontology/toplevel.htm and http://www.jfsowa.com/ontology/roles.htm
  supertype:  abstract__entity_without_spatial_feature (sumo)  e.g., knowledge, motivation, measure; properties or qualities as distinguished from any particular embodiment of the properties/qualities in a physical medium; instances of sumo#abstract can be said to exist in the same sense as mathematical objects such as sets and relations, but they cannot exist at a particular place or time without some physical encoding or embodiment
  subtype:  form__abstract_independent_thing  click here for details
     subtype:  schema__abstract_independent_continuant  click here for details
     subtype:  script__abstract_independent_occurrent  click here for details
  subtype:  proposition__abstract_relative_thing___situation_description  piece of information; this piece of information may be represented by content_bearing_object(s) such as a string, a sound or an icon; click here for details
     subtype:  description__abstract_relative_continuant  click here for details
     subtype:  history__abstract_relative_occurrent  click here for details
     instance:  "cats are furry animals"  "most cats are furry animals"
  subtype:  intention__abstract_mediating_thing  click here for details
     subtype:  reason__abstract_mediating_continuant  click here for details
     subtype:  purpose__abstract_mediating_occurrent  click here for details

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