A tolerance value is a set of durations which indicate the allowed tolerance for the indicated value, e.g. startafter=PT5M indicates that 5 minutes late is acceptable. A gluon takes vavailability. An interval takes no sub-components. types the content of the xCal attach element The artifact is here to handle elements that are not proper extensions of wsCalendar. The artifact Base is here for use in extending by other specifications allowing attributes from other namespaces to be added to ws-calendar-based schemas. The artifact Base is here for use in extending by other specifications, to to allow attributes from other namespaces to be added to ws-calendar-based schemas.