Function pm#generator (? -> causal_entity)
  exclusion:  attributive_relation  purpose  has-author  owned-by  owner  owner_of  leader  seller  customer  creator  spatial_origin  exploits  has_purpose  has_purpose_for_agent  measure  attribute  name  Date  value  rdf_reification_relation  support  example  syntax  has-magnitude
  supertype:  attributive_relation  who_relation
  subtype:  parent (? -> causal_entity)