Relation pm#relation_from_attribute_or_quality_or_measure (attribute_or_quality_or_measure,*)
  exclusion:  relation_from_situation  spatial_relation_from_entity_with_spatial_feature  relation_from_collection  relation_from_description_content/medium/container
  supertype:  relation_from/to_thing_of_common_kind  this type permits to categorize relations according to their signatures and hence offers (i) a concise way to set essential exclusion relations, and (ii) a systematic and easy-to-follow categorization
  subtype:  extension_fn__extensionfn (Attribute -> class)  a unary_function that maps an attribute into the class whose condition for membership is the attribute
  subtype:  relation_to_another_attribute_or_quality_or_measure (attribute_or_quality_or_measure,attribute_or_quality_or_measure)
     subtype:  measure (attribute_or_quality_or_measure,attribute_or_quality_or_measure)  e.g., [a weight, measure: 75 kg]
     subtype:  q_location__qlocation (quality,region)
        subtype:  has_quale__hasquale__ql (quality,quale)