Relation pm#experiencer (pm#situation,pm#causal_entity)
  subtype:  sumo#experiencer  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
  type:  pm#case_relation_type  the class of predicates relating the spatially distinguished parts of a process. e.g., the agent, patient or destination of an action, the flammable substance in a burning process, or the water that falls in rain
  supertype:  pm#case_relation__thematic_relation (pm#situation,*)
     supertype:  pm#relation_from_situation (pm#situation,*)
        supertype:  pm#relation_from/to_thing_of_common_kind (*)  this type permits to categorize relations according to their signatures and hence offers (i) a concise way to set essential exclusion relations, and (ii) a systematic and easy-to-follow categorization
           >part of:  pm#relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type
  supertype:  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 
        >part of:  pm#relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type