- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Tue, 02 Sep 2008 21:11:25 -0400 (EDT)
- To: schneid@fzi.de
- Cc: public-owl-wg@w3.org, team-owl-chairs@w3.org
Here are my comments on the OWL 2 Full Semantics. I haven't made review comments because I read the document while I was not connected to the web, and thus couldn't edit the document. In general I think that the document is quite good. I have a number of minor changes listed here. I also have a comment that is more general than the document itself: - owl:distinctMembers should be deprecated, as its function is handled by owl:members Initial comments on the document: - Vocabulary changes xsd:short - add to list of datatypes xsd:anyURI - replace owl:anyURI by xsd:anyURI owl:NAryDatatype - remove owl:datatypeArity - remove owl:Annotation - add as class, subset of IR - "owlV" is not used after being defined. I suggest removing it from the definition of the OWL 2 Full vocabulary. - The deprecation of owl:DataRange should say The URI reference rdfs:Datatype SHOULD be used instead. - Definition 3.2 should also require that the datatype and facet names of D be in V. - Definition 3.2 should read "... let V be a vocabulary that includes ...". - What are the "constraints in this section" referred to in Definition 3.2? I don't see any. - Definition 3.3 and 3.4: Satisfaction of RDF graphs is not defined in this document. If this means some RDF satisfaction, then you need to point there. If not, you need to define satisfaction. - Definition 3.3: Q is not used. - The semantic conditions are additions to also the D-entailment conditions, I think. The first sentence of Section 4 should be changed accordingly. - ICEXT(owl:NamedIndividual) = IR is probably incorrect, there are only countably many named individuals, but potentially uncountably many resources. Should be <= IR. - Table 4.1 - add column for description, e.g., Domain of discourse / Literal Values / Ontologies / Classes / Datatypes / ... - owl:NAryDatatype is no longer in the RDF mapping owl:datatypeArity is no longer in the RDF mapping - Replace "<= empty set" with "= empty set" in several places. - IEXT(IS(owl:object)) <= ICEXT(IS(owl:Axiom)) x IR is wrong, as it states that annotated annotations are axioms. It should be IR x IR. Similarly for owl:predicate and owl:subject. (This may be because the document does not yet handle annotations on annotations.) - owl:allValuesFrom should be <= owl:Restriction x IC. - owl:TopDataProperty has wrong domain. It should be = IR x ILV. - Table 4.7 needs to be augmented with the conditions for nary some/all as follows: if l is the sequence p1,...,pn in IDP - <x,c> in IEXT(IS(owl:someValuesFrom)) <x,l> in IEXT(IS(owl:onProperties)) then ICEXT(x) = { y | exists z1, ..., zn <y,zi> in IEXT(pi) for each 1<=i<=n and <z1,...,zn> in ICEXT(c) } - <x,c> in IEXT(IS(owl:allValuesFrom)) <x,l> in IEXT(IS(owl:onProperties)) then ICEXT(x) = { y | forall z1, ..., zn <y,zi> in IEXT(pi) for each 1<=i<=n imply <z1,...,zn> in ICEXT(c) } - The above change removes the need for Table 4.9. - The last part of the paragraph before Table 4.10 should read something like: Note that only the additional semantic conditions are given here and that the other RDFS conditions on this vocabulary are retained. - There is no definition of sequence. - Semantic conditions should be provided for property chains directly, as in: Table 4.11: Property Chains if l sequence of p1,...,pn in IR then <x,l> in IEXT(IS(owl:propertyChain)) IFF x,p1,...pn in IP IEXT(x) = IEXT(p1) o ... o IEXT(pn) - The x,y,z in Table 4.15 should be explicitly quantified over IR in the RHS of the table. - I believe that Table 4.16 should have x in CEXT(c), y in CEXT(c). Also Table 4.16 is missing quantifiers for the zi. I believe that they should be existentially quantified. - Table 4.18 is missing a membership symbol. - Table 4.18 already almost handles annotations on annotations, I think, provided that the domain of the OWL reification properties are changed as suggested. However, I think that it would be better to change Table 4.18 and its introduction as follows: Table 4.18 lists the semantic conditions for the OWL vocabulary used for some axiom annotations and for annotations on annotations. Both these kinds of annotations employ a reified version of a triple representing either the annotated axiom or the annotated annotation. The semantic conditions below recovers the triple itself from the reified version. Table 4.18: Reified Axioms and Annotations - if x in ICEXT(IS(owl:Axiom)) <x,u> in IEXT(IS(owl:subject)) <x,p> in IEXT(IS(owl:predicate)) <x,w> in IEXT(IS(owl:object)) then <u,w> in IEXT(p)) - if x in ICEXT(IS(owl:Annotation)) <x,u> in IEXT(IS(owl:subject)) <x,p> in IEXT(IS(owl:predicate)) <x,w> in IEXT(IS(owl:object)) then <u,w> in IEXT(p)) - There needs to be a section on the differences from OWL 1 Full semantics, talking about comprehension principles, at least. - Why is there a partial comprehension principle for propertychains and subpropertyof (in Table 4.11)? See suggestion for Table 4.11 above. - Why do AllDifferent, AllDisjointClasses, and AllDisjointProperties have partial comprehension principles? I suggest removing second half of Table 4.13 or moving it to Section 6. - Why are there comprehension principles for negative property assertions? I suggest removing second half of Table 4.17 or moving it to Section 6. - I have not examined Section 6 closely. I am thinking about the comprehension principles and how to best handle them. I may have a proposal for further changes in this area. Peter F. Patel-Schneider Bell Labs Research
Received on Wednesday, 3 September 2008 01:12:11 UTC