On Jul 1, 2008, at 1:32 PM, Boris Motik wrote: > If we absolutely need +inf, -inf, and NaN, then I'd say we need to > add them to owl:real, and then make all other numeric datatypes > subsets of that datatype. Yes, I was going to suggest that. Since it's ours to define anyways. > Finally, do we really care about +inf, -inf, and NaN? XML Schema > might care, but again, XML Schema is a schema and not an ontology > language. XML Schema does not need to do any reasoning on the > datatypes; it only needs to perform straightforward validation. > This is why I suggested to change xsd:float: we probably don't want > to reason about the properties of floating point arithmetic. We can > keep the name to make people happy. People will be able to put > values into their ontology that can be written in the form of > floats and will be perfectly happy with that; for the most part, > they won't be able to detect the difference. The issue is how easy or hard it is to carry data around in an OWL file. If you have some quantity of data and you put it in OWL and the 3 NaN that are in it make the system not able to proceed because there is a syntax error, and you have to stop and figure out some ugly workaround,then this is a problem. It's a little like annotations. They don't have the usual logical semantics, we don't do reasoning on them, but they are important, nonetheless. I realize that these complicate the reasoning a bit. For one thing, its not clear to me whether we can still say that xsd:float is a bounded subset of the reals, because of the INFs. -Alan
Received on Tuesday, 1 July 2008 17:53:10 UTC