Relation pm#relation_from_a_domain__thing_in_domain (domain,?)
  closed_exclusion:  relation_from_a_thing_that_is_not_a_domain
  supertype:  domain_related_relation__domain-related-thing
  instance of:  virtual_relation_type
  subtype:  subdomain__true-subdomain (domain,domain)  in WebKB-2, ">part" is an abbreviation of this relation since it is not  
 a part relation nor a specialization relation but a mix of both; 
 for details, see http://www.webkb.org/kb/it/o_domain/d_field_of_study.html
  subtype:  domain_object (domain,?)
     subtype:  core_domain_object__central_object_of_domain (domain,?)