Relation pm#relation_from_process_only (process,?)
  subtype:  goal  triggering_event  ending_event  precondition  postcondition  input  input_output  sub_process  method  from/to_place  process_attribute
  supertype:  case_relation__thematic_relation (situation,*)
     supertype:  relation_from_situation (situation,*)
        supertype:  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:  relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type