[pm#graph1_on_description
     [any pm#description (^$(no inheritance)$^),
          pm#descr of: a pm#thing,
          pm#descr_container: a pm#description_container,
          may have for pm#url: a pm#URL,
          pm#description_instrument: a pm#description_medium,
          may have for pm#language: a pm#description_medium,
          may have for pm#format: a #data_format,
          pm#author: 1 pm#causal_entity,
          pm#authoring_date: a pm#time_measure,
          may have for pm#proof: a pm#description,
          may have for pm#example: a pm#description,
          may have for dc#Contributor: a pm#entity,
          may have for dc#Source: a pm#entity,
          may have for pm#url: a pm#URL,
          may have for pm#relation_from_description (^$(explore)$^): a pm#thing]
];


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