W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > November 2001

RE: Literals: lexical spaces and value spaces

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Tue, 13 Nov 2001 19:38:45 -0600
Message-Id: <p05101043b81779b0e609@[65.212.118.147]>
To: Patrick.Stickler@nokia.com
Cc: w3c-rdfcore-wg@w3.org, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
>........
>>  >This, of course, presumes that we are not asserting the
>>  >global constraint on data types that the lexical space of
>>  >any data type must be a proper subset of the lexical space
>>  >of all of its superordinate types.
>>
>>  Ah, but we must make that assumption; I have already conceded
>>  that point.
>
>But XML Schema simple data types fail that requirement. Thus,
>we cannot make that assumption. Only value spaces for XML
>Schema simple types are proper subsets of the value spaces
>of their superordinate types. Lexical space is specific to
>each type. I had hoped that was not the case, but it is.

Can you please elaborate on this point, with an example, as it seems 
rather important.

I was under the impression that XML Schema datatypes DID satisfy the 
required conditions. To fail, we need the following circumstances: 
two datatypes D1 and D2 with the value space of D1 being a subset of 
that of D2, and the lexical space of D1 intersecting that of D2, and 
D1 having a different, and incompatible, lexical-to-value mapping on 
that intersection from that used by D2.

Pat
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Received on Tuesday, 13 November 2001 20:38:42 EST

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