Returns the xs:dateTime that is a given duration before a specified
xs:dateTime (or after, if the duration is negative).
xs:dateTime an and
xs:dayTimeDuration valuesop:subtract-dayTimeDuration-from-dateTime( $arg1 as xs:dateTime,$arg2 as xs:dayTimeDurationxs:dateTimeThe function returns the xs:dateTime computed by negating
$arg2 and adding the result to the value of $arg1 using the
function op:add-dayTimeDuration-to-dateTime.
The expression op:subtract-dayTimeDuration-from-dateTime(xs:dateTime("2000-10-30T11:12:00"),
xs:dayTimeDuration("P3DT1H15M")) returns xs:dateTime("2000-10-27T09:57:00").