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On Mon, 10 Jan 2005, Childress,Eric wrote: >g. Soft termini (i.e. the outer bounds for one or more termini is known or >can be associated with a known period, but one or both of the exact >boundaries of the event referenced are not known) >-- I suggest this approach because this issue is concievably a sub-category >of most of the other categories (or perhaps arguably an inherent feature of >most large dates) ; rather than add "and soft termini" or something similar >to the various date categories, maybe it's simply easier to recognize the >issue as a category in its own right?) ... >It strikes me that we may need to begin compiling use cases for each of the >categories? If the WG agrees, I'll likely return to the WG to solicit a >volunteer to act as use case master. I think it is worth recognising this as an issue. And I think use cases are very important. One is in historical work, where over time one refines the information about a particular object or document. For example, on their discovery one might have dated the Dead Sea Scrolls as being compiled between some absolute date, and some event which was in fact itself only roughly dated. We *could* do this by modelling times as ranges automatically, where a specified single time (the Hejira year 1473, for example) actually means the largest valid range covered by that time - in other words, from the beginning of 1 Awal Muharam wherever it occurs first, until the last day of Dhou-al-hijja wherever it occurs last, and the gregorian date-time 2005-01-11T11:38+0100 as the range starting at the beginning of the first second of that minute, and ending with the last second of it. (This already includes time-zone information, which has a relatively simple model specified with weel-understood encodings, something that might not be the case for Hejira calendars which in any case are more complex). For most purposes, I think being given a single time doesn't need any more processing, since the fact that it is a range isn't important to the use case. But it would be worth specifying (as XML schema does) that we are already talking about something with a start and end. Thus we could model all "dates" (including times, for people who want them) as a thing with a start and end, specifiable themselves as a time (and thus a range). In the simple case there is something like a gregorian date whose termini are understood from the encoding, in the medium case there are two such dates, and in the complex case one or other terminus can itself be specified as a time range. (This will make it easier to say that something falls between the Tang dynasty and the wandering in the desert of the Israelites, as soon as we have a reasonable encoding for those...) cheers Chaals