There are invalid durations among the examples for op:duration-example (section 10.4.5.1) of XQuery 1.0 and XPath 2.0 Functions and Operators, W3C Recommendation 23 January 2007. Fourth, fifth, seventh example should be respectively fixed from ``xs:dayTimeDuration("PT0D")'' to ``xs:dayTimeDuration("P0D")'', ``PT365D'' to ``P365D'', and ``PT10D'' to ``P10D''.
Thank you for pointing out these corrections. They will appear in due course as erratum E20. As this is an editorial error rather than a substantive one, and as we are making the change requested, I will mark the problem as fixed and closed.