A special kind of Situation that allows to include time indexing for the hasPart relation in situations. For example, if a Situation s 'finally, my bike has a luggage rack' isSettingFor the entity 'my bike' and the TimeIntervals 'now', or more specifically '29March2021', we need to have a time-index the part relation. With Parthood, we use includesWhole and includesPart properties. This can be done similarly for other arguments of parthood, e.g. location, configuration, topology, etc. Concerning the possible property characteristics reused from mereology (transitivity, asymmetry, reflexivity), they need to be implemented by means of rules (or, in a limited way, property chains using the binary hasPart or hasProperPart properties). A key is also added to ensure identification constraints of time-indexed parthood.