From https://labs.etsi.org/rep/saref/saref-portal/-/issues/50 _SAREF4CITY uses the W3C Time Ontology and declares class time:TemporalEntity, time:Instant, and time:Interval. It uses time:TemporalEntity in local restrictions on classes s4city:Event and s4city:KeyPerformanceIndicator._ Proposal: _SAREF Extensions should not promote the use of the W3C Time Ontology for time units over other ontologies of units of measure._ _In SAREF Extensions, declare the concepts from W3C Time ontology that are needed, for example:_ ``` time:TemporalUnit a owl:Class ; rdfs:isDefinedBy time: . time:TemporalEntity a owl:Class ; rdfs:isDefinedBy time: . ``` _SAREF Extensions should only declare the concepts that they use._ _Favour xsd:dateTime and xsd:duration if modeling with DPs could be enough. Especially if only instants are expected._ Remove unused classes time:Instant, and time:Interval Changes have to be performed in the OWL code, TS, diagrams, documentation, tests and examples