Subject A can either be concept that is or has an 'Operation' function, or an entity outside of an ontology (or an ontology concept in a role of an entity being semantically annotated) that has an 'Operation' function or is an 'Operation'. Object B can be any concept or entity. In EDAM, only 'has_output' is explicitly defined between EDAM concepts ('Operation' 'has_output' 'Data'). The inverse, 'is_output_of', is not explicitly defined.