[pm#graph1_on_transaction
     [any #transaction (^$(no inheritance)$^),
          pm#object: a pm#thing,
          pm#place: a #region,
          pm#seller: a menu#person_or_organization (^$(explore 1)$^),
          pm#customer: a menu#person_or_organization (^$(explore 1)$^),
          #asking_price: an #asking_price,
          #purchase_price: a #purchase_price,
          may have for pm#relation_from_situation_to_time (^$(explore)$^): a pm#time_measure,
          may have for pm#doer/object/result/place (^$(explore)$^): a pm#thing,
          may have for pm#relation_from_situation (^$(explore)$^): a pm#thing]
];