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This page summarizes discussion on question of how to describe repeated events using Schema.org vocabulary.
Initial thread: Proper schema.org markup of repeating / recurring events?, Sean Carlos 20 Dec 2011.
I have several cases of repeating / recurring events, such as a monthly business networking lunch, where the only data elements which change from event to event are the dates.
It appears to me that schema.org doesn't yet address this particular use case?
In a similar vein, the schema.org documentation is silent on how to markup multiple events which occur at the same venue. There is an example specific to Google: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=164506 but it would be nice to see this officially documented for schema.org AND clarity provided regarding the order of the data - i.e. the possibility to list each event occurrence then the venue, i.e. putting the event where it belongs, before the venue.
Martin Hepp advises that it may be better to materialise descriptions of each event, rather than rely too strongly on rules.
Research and reading
There is also some earlier work on representing iCalendar in RDF, see http://www.w3.org/wiki/RdfCalendarDocumentation and http://www.w3.org/TR/rdfcal/ as well as the fairly widely adopted hcalendar work from the Microformats community, http://microformats.org/wiki/hcalendar (@todo: find hcal's approach to repeats).