Relation pm#relation_from_process_only (pm#process,?)
  subtype:  pm#goal  pm#triggering_event  pm#ending_event  pm#precondition  pm#postcondition  pm#input  pm#input_output  pm#sub_process  pm#method  pm#from/to_place  pm#process_attribute
  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