Re: Ill-typed vs. inconsistent?

On Nov 12, 2012, at 10:20, Sandro Hawke <sandro@w3.org> wrote:

> On 11/12/2012 02:58 AM, Pat Hayes wrote:
>> On Nov 8, 2012, at 1:13 PM, Richard Cyganiak wrote:
>> 
>>> What's the relevance of the distinction between “graphs containing ill-typed literals” and “inconsistent graphs” in the Semantics?
>> The relevance is that it is quite possible to say sensible (and therefore consistent) things about ill-typed literals, such as that they are ill-typed.
>> 
>>> The text stresses that the presence of an ill-typed literals does not constitute an inconsistency.
>>> 
>>> But why does the distinction matter?
>> I am not sure what you mean by "the distinction" here. Why would you expect that an ill-typed literal would produce an inconsistency? Why would the presence of an ill-typed literal make a triple false?
>> 
>>> Is there any reason anybody needs to know about this distinction who isn't interested in the arcana of the model theory?
>> I'm not sure what you consider to be "arcana". Someone who cannot follow the model theory probably shouldn't be using RDF.
> 
> Pat, I think a lot of people should be using RDF who are not interested in the model theory.  It's a bit like people buys nails at the hardware store without knowing all the materials characteristics of the metal used.  (Whether they *can* understand the materials science is irrelevant, of course.)

+1, of course.  I can't believe Pat actually meant that…

Regards,
Dave


> 
>     -- Sandro
>>> From the perspective of someone who authors RDF data, or works with RDF data, they both seem like belonging to the same class of problem, and I'm a bit at a loss as to how to explain the difference.
>> To me they seem quite obviously different, so apparently I am not following your intuition here. FWIW, one should *not* think of inconsistency as a kind of error condition. (Maybe the semantics text should spend a little time explaining this point.)
>> 
>>> (I know how both terms are defined and what conditions exactly cause them; the question is about why the spec insists that ill-typed literals do not cause a graph to be inconsistent.)
>> My question, in reply, would be to ask why anyone would think it would.
>> 
>> Pat
>> 
>>> Best,
>>> Richard
>>> 
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