"If your application needed to represent a future recurring event, such as the time of a regular teleconference, an xs:dateTime value such as "2010-07-10T07:00:00-07:00" with an associated xs:duration field of "P7D" (i.e. weekly) would not tell you if the meeting should occur at a different actual wall time following the next daylight saving transition, and, if so, which t