[pm#graph1_on_collection
     [any pm#collection (^$(no inheritance)$^),
          may have for pm#member: a pm#thing,
          may have for pm#relation_from_collection (^$(explore)$^): a pm#thing,
          may have for pm#creator (^$(explore)$^): a #person,
          may have for pm#url: a pm#URL]
];