- From: Peter Patel-Schneider <pfpschneider@gmail.com>
- Date: Wed, 28 Nov 2012 13:45:02 -0500
- To: RDF WG <public-rdf-wg@w3.org>
- Message-ID: <CAMpDgVwPn8A34m53sFEk-qTREJNTGMMFaMKOqLmPOi2RoCAxLA@mail.gmail.com>
I have a few changes to wording to correct what I see as errors. Something needs to be done to fix the situation with respect to blank nodes, but the issue note already warns about this so there is no need to hold up publication right now. I think that something needs to be done about social meaning. I have suggestions below. As the sections involved at non-normative, I don't think that publication needs to be held up until the problem is resolved. Minor grammar changes: 0.1/ Be consistent with commas before "being". 0.2/ string, numbers -> strings, numbers 0.3/ "semantics" should be reserved for the model-theoretic semantics. Use "meaning" instead in other situations. 0.4/ "should" should be avoided except when it is "SHOULD". Significant changes: A/ I worry about Section 1.3 and the last bit of Section 6. It appears to me that this is edging back towards social meaning, which was ripped out of RDF the last time around. Initial suggestion for Section 1.3: 1.3 The Referent of an IRI The resource denoted by an IRI is also called its referent. What exactly is denoted by any given IRI is not defined by this specification. Basic guidelines for determining the referent of an IRI are provided in other documents, like Architecture of the World Wide Web, Volume One [WEBARCH] and Cool URIs for the Semantic Web [COOLURIS]. A very brief, informal and partial account of these guidelines follows: - IRIs have global scope: An IRI is assumed to denote the same resource regardless of where the IRI occurs. - By social convention, The IRI owner [WEBARCH] provides the can establish the intended referent by means of a specification or other document that explains what is denoted. <<RDF-SCHEMA is special here, FOAF would be a much better example>> For example, [RDF-SCHEMA] specifies the referents of various IRIs that start with http://www.w3.org/2000/01/rdf-schema#. - A good way of providing the intended referent is to set up the IRI so that it dereferences [WEBARCH] to a document. Such a document can, in fact, be an RDF document that describes the denoted resource by means of RDF statements. Suggestion for the last bit of Section 6: It is a good idea to, whereever reasonable, set up fragment identifiers in RDF-bearing representations in a way that is consistent with non-RDF representations. For example, if the fragment chapter1 identifies a document section in an HTML representation of the primary resource, then the IRI <#chapter1> should be taken to denote that same section in all RDF-bearing representations of the same primary resource. B/ Something needs to be done to Section 3.4. There should be some wording here to indicate that blank nodes can be shared between RDF graphs, but that simply reusing a blank node identifier between to unrelated graphs results in different blank nodes. There is more work needed here as well. Other changes: 1/ Change [required]: This document defines an abstract syntax (a data model) which serves to link all RDF-based languages and specifications, including: - Serialization syntaxes for storing and exchanging RDF (e.g., Turtle [TURTLE-TR] and RDF/XML [RDF-SYNTAX-GRAMMAR]), - the SPARQL Query Language [RDF-SPARQL-QUERY], - the RDF Vocabulary Description Language [RDF-SCHEMA], - a formal model-theoretic semantics for RDF [RDF-MT]. to: This document defines an abstract syntax (a data model) for RDF. Concepts defined in this document are vital to understanding any aspect of RDF, and support - serialization syntaxes for storing and exchanging RDF (e.g., Turtle [TURTLE-TR] and RDF/XML [RDF-SYNTAX-GRAMMAR]), - the RDF Vocabulary Description Language (RDFS) [RDF-SCHEMA], - the formal model-theoretic semantics for RDF and RDFS [RDF-MT], and - the SPARQL Query Language [RDF-SPARQL-QUERY]. ********************* 2/ Change [strongly recommended]: The core structure of the abstract syntax is a collection of triples, each consisting of a subject, a predicate and an object. A set of such triples is called an RDF graph. This can be illustrated by a node and directed-arc diagram, in which each triple is represented as a node-arc-node link; hence the term “graph”. to: The core structure of the abstract syntax for RDF is a set of triples, each consisting of a subject, a predicate and an object. A set of such triples is called an RDF graph. An RDF graph can be visualized as a node and directed-arc diagram, in which each triple is represented as a node-arc-node link. ********************* 3/ Change [picky wording change]: There may be three kinds of nodes in an RDF graph: IRIs, literals, and blank nodes. to: There can be three kinds of nodes in an RDF graph: IRIs, literals, and blank nodes. ********************* 4/ Change [wording change]: Any IRI and literal denotes to: Any IRI or literal denotes ********************* 5/ Change [very picky wording change]: holds between the resources denoted by the subject and object. to: holds from the resource denoted by the subject to the resource denoted by the object. ********************* 6/ Change [strongly recommended - there is no need to have referents to define a vocabulary]: An RDF vocabulary is a collection of IRIs with clearly established referents intended for use in RDF graphs. to: An RDF vocabulary is a collection of IRIs intended for use in RDF. ********************* 7/ Change [strongly recommended]: An RDF dataset is a collection of RDF graphs. All but one are named graphs associated with an IRI. The last one is the unnamed default graph, and is often used to hold triples that involve the graph names. A common use of RDF datasets is to hold snapshots of multiple RDF sources. to: An RDF dataset is a collection of RDF graphs. All but one of these graphs have an associated IRI. These graphs are called named graphs, and the IRI is called the name of the named graph. The remaining graph does not have an associated IRI. It is called the default graph of the dataset. There are many possible uses for RDF datasets. One such use is to hold snapshots of multiple RDF sources. It is common to have the default graph contain triples that involve the names of the other graphs in the dataset. ********************* 8/ Change [required - don't dump on the semantics]: This treatment of RDF graphs as logical expressions is normatively defined in the RDF Semantics specification [RDF-MT], using the formalism of Model Theory. to: The logical meaning of RDF graphs is normatively defined in the RDF Semantics specification [RDF-MT], using a model-theoretic semantics. ********************* 9/ Change [grammar and clarification]: An RDF graph A entail another RDF graph B if every possible arrangement of things in the world that makes A true also makes B true. If the truth of A is presumed or demonstrated, then the truth of B can be inferred. to An RDF graph A entails another RDF graph B if every possible arrangement of the world that makes A true also makes B true. When A entails B, if the truth of A is presumed or demonstrated then the truth of B is established. ********************* 10/ Change [grammar]: A concrete RDF syntaxes to: Concrete RDF syntaxes ********************* 11/ Change [be cleaner about RDF meaning]: semantics, which lies exclusively in the encoded graph or dataset. to: meaning, which is exclusively mediated by the encoded graph or dataset. ********************* 12/ Change [required, is currently false]: This transformation does not change the meaning of an RDF graph, provided that the Skolem IRIs do not occur anywhere else. It does however permit the possibility of other graphs subsequently using the IRI to also refer to the same entity, which was not possible when the node was blank. to: This transformation does not appreciably change the meaning of an RDF graph, provided that the Skolem IRIs do not occur anywhere else. It does however permit the possibility of other graphs subsequently using the Skolem IRIs, which is not possible for blank nodes. ********************* 13/ Change [garden path grammar]: An RDF Dataset is a collection of RDF graphs and comprises: to: An RDF Dataset is a collection of RDF graphs, and comprises: ********************* 14/ Change [grammar and false?]: RDF re-uses the XML Schema built-in datatypes to: RDF uses many XML Schema datatypes ********************* 15/ Change [currently different from definition in RDF semantics]: A datatype map is an implementation-defined set of <IRI, datatype> pairs such that no IRI appears twice in the set and the IRI denotes the datatype. It can be seen as a function from IRIs to datatypes. to: A datatype map is an implementation-defined set of <IRI, datatype> pairs such that no IRI appears twice in the set. It can be seen as a function from IRIs to datatypes. ********************* 16/ Change [false]: Otherwise, the literal is ill-typed, and no literal value can be associated with the literal. Such a case, while in error, is not syntactically ill-formed. to: Otherwise, the literal is ill-typed, and no literal value can be associated with the literal. Ill-typed literals are not syntactically ill-formed and, while ill-typed literals are not normal, just their use does not make an RDF graph inconsistent.
Received on Wednesday, 28 November 2012 18:45:30 UTC