http://terminology.hl7.org/StructureDefinition/ext-mif-relationship-symmetry|0.0.34

Indicates if the relationship always holds in the reverse direction as well (symetric), never holds in the reverse direction as well (antisymetric)

element_id	types
Extension
Extension.extension
Extension.url	uri
Extension.value[x]	code
Extension
Extension.id	http://hl7.org/fhirpath/System.String
Extension.extension	Extension
Extension.url	uri
Extension.value[x]	code