[graph1_on_spatial_object
     [any spatial_object (^$(no inheritance)$^),
          spatial_characteristic (^$(explore 1)$^): a spatial_attribute_or_quality_or_measure,
          relation_to_another_spatial_object (^$(explore 2)$^): a spatial_object,
          may have for owner: a person_or_organization (^$(explore 1)$^),
          monetary_value: a monetary_value,
          may be object of: a commercial_transaction (^$(explore 1)$^),
          place of: a situation]
];