Relation pm#who_relation__whorelation (*)
  supertype:  wh-/how_relation  this type permits to categorize relations according to the usual who/what/why/where/when/how questions ; this is a traditional but very subjective and ineffective way of categorizing relations 
  subtype:  agent__doer (situation [48..*],entity [49..*])
     subtype:  organizer (situation,causal_entity)
     subtype:  participant (situation,causal_entity)
     subtype:  seller__vendor___vender (situation -> goal_directed_agent)
     subtype:  customer__client___buyer__buyer___purchaser__purchaser___vendee (situation,goal_directed_agent)
     subtype:  responsible_agent__responsibleagent (situation,causal_entity)
     subtype:  agent (process,agentive_physical_object)  the 2nd argument is an active determinant, animate or inanimate, of the process
  subtype:  initiator (situation,causal_entity)
  subtype:  experiencer (situation,causal_entity)
     subtype:  experiencer (process,agentive_physical_object)  e.g., Yojo is the experiencer of seeing in 'Yojo sees the fish'; unlike agent, this relation does not entail a causal relation between the arguments
  subtype:  owner (?,causal_entity)  this is not a function: 0..N owner allowed
     subtype:  sole_owner (? -> causal_entity)
  subtype:  generator (? -> causal_entity)
     subtype:  parent (? -> causal_entity)
  subtype:  creator (entity,entity)
     subtype:  Creator (entity,entity)  to specify an entity primarily responsible for making the content of a resource
        subtype:  author (description,causal_entity)
           subtype:  main_author (description,causal_entity)
           subtype:  co-author (description,causal_entity)