From: Jeff Heflin ([email protected])
Date: 03/05/01
First, I apologize for missing the last two telecons: I've been going on job interviews. Nevertheless, it looks like some good progress has been made without me... maybe I should miss more telecons! ;-) Here's my comments on the various specs available at http://www.daml.org/2001/03/daml+oil-index daml+oil.daml: -------------- 1) rdfs:range of maxCardinality is http://www.w3.org/2000/01/rdf-schema#nonNegativeInteger, I assume this should be http://www.w3.org/2000/10/XMLSchema#nonNegativeInteger 2) ditto for rdfs:range of cardinality, minCardinalityQ, maxCardinalityQ, and cardinalityQ 3) Why is UnambiguousProperty a subclass of AbstractProperty? Can't there be Datatype properties that are unambiguous? For example, numberOfMonth (with domain Month, and range nonNegativeInteger)? daml+oil-walkthru: ------------------ 1) In the section "Defining individuals", it says "Note that to use datatype values, we had to provide an XML Schema datatype along with the value. This datatype is used to parse the lexical representation into an actual value." I thought that this was optional, especially if the DAML ontology defines the range. I believe Mike Dean had argued earlier that if we had to tag the type of each value, then it would be very inconvenient for users (now come the counter-arguments about how most users will use tools to do the markup anyway...). Personally, it seems a little overboard to me, and I'd like to have a choice as to whether or not I provide the datatype with every value I specify or take my chances that any consuming agent will download the appropriate ontology before parsing. If I'm preaching to the converted, then maybe we need to be a little clearer in the Walkthru document. If this was voted on at a telecon that I missed, then I guess I can't complain. reference.html: --------------- 1) In the section "Property restriction", the first paragraph has an unifinished sentence "Both kinds of restrictions..." 2) My comment for datatype values above (daml+oil-walkthu #1) also applies to the Datatype Values section 3) My comment on UnambiguousProperty above (daml+oil.daml #3) also applies in the "Property element" section model-theoretic-semantics.html: ------------------------------- 1) The text switches into teletype mode during the sentence "The IR mapping maps abstract properties into subsets of AD x AD and datatype properties into subsets of AD x DD." and stays that way for the rest of the document. I assume a missing </tt> tag is the culprit. 2) The document says "A method for asserting the equality and inequality of individuals would be helpful." Why can't equivalentTo be used to assert the equality of two individuals? 3) To return to an old debate, is it really necessary to express the semantics for AbstractProperties and DatatypeProeperties separately? For example, the document has: Syntactic Structure: <rdf:type,?R,Restriction> <onProperty,?R,?P> <rdf:type,?P,AbstractProperty> <toClass,?R,?C> Semantic Constraint: x in IC(?R) iff IR(?P)({x}) <= IC(?C) and: Syntactic Structure: <rdf:type,?R,Restriction> <onProperty,?R,?P> <rdf:type,?P,DatatypeProperty> <toClass,?R,?C> Semantic Constraint: x in IC(?R) iff IR(?P)({x}) <= IC(?C) Note that the only different in the two is that the type for one is AbstractProperty and the type for the other is DatatypeProperty. Their semantic constraints are equivalent, so why not collapse them? We know Property is superclass of AbstractProperty and DatabaseProperty, so we could state this more simply as: Syntactic Structure: <rdf:type,?R,Restriction> <onProperty,?R,?P> <rdf:type,?P,Property> <toClass,?R,?C> Semantic Constraint: x in IC(?R) iff IR(?P)({x}) <= IC(?C) Jeff
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