Relation pm#who_relation__whorelation (*)
  supertype:  pm#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:  pm#agent__doer (pm#situation [48..*],pm#entity [49..*])
     subtype:  pm#organizer (pm#situation,pm#causal_entity)
     subtype:  pm#participant (pm#situation,pm#causal_entity)
     subtype:  pm#seller__vendor___vender (pm#situation -> pm#goal_directed_agent)
     subtype:  pm#customer__client___buyer__buyer___purchaser__purchaser___vendee (pm#situation,pm#goal_directed_agent)
     subtype:  pm#responsible_agent__responsibleagent (pm#situation,pm#causal_entity)
     subtype:  sumo#agent (sumo#process,dl#agentive_physical_object)  the 2nd argument is an active determinant, animate or inanimate, of the process
  subtype:  pm#initiator (pm#situation,pm#causal_entity)
  subtype:  pm#experiencer (pm#situation,pm#causal_entity)
     subtype:  sumo#experiencer (sumo#process,dl#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:  pm#owner (?,pm#causal_entity)  this is not a function: 0..N owner allowed
     subtype:  pm#sole_owner (? -> pm#causal_entity)
  subtype:  pm#generator (? -> pm#causal_entity)
     subtype:  pm#parent (? -> pm#causal_entity)
  subtype:  pm#creator (pm#entity,pm#entity)
     subtype:  dc#Creator (pm#entity,pm#entity)  to specify an entity primarily responsible for making the content of a resource
        subtype:  pm#author (pm#description,pm#causal_entity)
           subtype:  pm#main_author (pm#description,pm#causal_entity)
           subtype:  pm#co-author (pm#description,pm#causal_entity)