The Resource Description Framework (RDF) is a framework for
representing information in the Web.
RDF Concepts and Abstract Syntax defines an abstract syntax
on which RDF is based, and which serves to link its concrete
syntax to its formal semantics. It also includes discussion of
design goals, key concepts, datatyping, character normalization
and handling of URI references.
This version is a mess at the moment.
This version is modified from the
last call
version with changes
as listed in the change log. These are
substantive changes as approved by the RDF Core WG, and
editorial changes made, typically in response to
last call comments, at the discretion of the editors.
The Resource Description Framework (RDF) is a framework for
representing information in the Web.
This document defines an abstract syntax on which RDF is based,
and which serves to link its concrete syntax to its formal
semantics. It also includes discussion of design goals,
key concepts, datatyping, character normalization
and handling of URI references.
Normative documentation of the RDF core falls into the following
areas:
Within this document, normative sections are explicitly labelled as such.
Explicit notes are informative.
The framework is designed so that vocabularies can be layered on
top of a core. The RDF core and RDF vocabulary definition (RDF schema)
languages
[RDF-VOCABULARY] are the first
such vocabularies.
Others (cf. OWL [OWL] and
the applications in the primer
[RDF-PRIMER]) are in development.
In section 2,
the background rationale and design goals
are introduced.
Key concepts follow in section 3.
RDF's abstract syntax is a graph, which can be serialized using
XML (but which is quite distinct from XML's tree-based infoset [XML-INFOSET]). The abstract syntax
captures the fundamental structure of RDF, independently of any
concrete syntax used for serialization. The formal semantics of RDF
are defined in terms of the abstract syntax. XML content of
literals is described in section
5, and the abstract syntax is defined in section 6 of this document.
Section 7 discusses the role of fragment
identifiers in URI references used with RDF.
RDF has an abstract syntax that reflects a simple graph-based
data model, and formal semantics with a rigorously defined notion
of entailment providing a basis for well founded deductions in RDF
data.
The development of RDF has been motivated by the following uses,
among others:
- Web metadata: providing information about Web resources and
the systems that use them (e.g. content rating, capability
descriptions, privacy preferences, etc.)
- Applications that require open rather than constrained
information models (e.g. scheduling activities, describing
organizational processes, annotation of Web resources, etc.)
- To do for machine processable information (application data)
what the World Wide Web has done for hypertext: to allow data to
be processed outside the particular environment in which it was
created, in a fashion that can work at Internet scale.
- Interworking among applications: combining data from several
applications to arrive at new information.
- Automated processing of Web information by software agents:
the Web is moving from having just human-readable information to
being a world-wide network of cooperating processes. RDF provides
a world-wide lingua franca for these processes.
RDF is designed to represent information in a minimally
constraining, flexible way. It can be used in isolated
applications, where individually designed formats
might be more direct and easily understood, but RDF's generality offers greater value from
sharing. The value of information thus increases as it becomes
accessible to more applications across the entire Internet.
The design of RDF is intended to meet the following goals:
- having a simple data model
- having formal semantics and provable inference
- using an extensible URI-based vocabulary
- using an XML-based syntax
- supporting use of XML schema datatypes
- allowing anyone to make statements about any
resource
RDF has a simple data model that is easy for applications to
process and manipulate. The data model is independent of any
specific serialization syntax.
Note: the term "model" used here in "data model" has a
completely different sense to its use in the term "model theory".
See [RDF-SEMANTICS]
for more information about "model
theory" as used in the literature of mathematics and logic.
RDF has a formal semantics which provides a dependable basis for
reasoning about the meaning of an RDF expression. In particular, it
supports rigorously defined notions of entailment which provide a
basis for defining reliable rules of inference in RDF data.
The vocabulary is fully extensible, being based on URIs with
optional fragment identifiers (URI references, or
URIrefs). URI references are used for naming all kinds
of things in RDF.
The other kind of value that appears in RDF data is a
literal.
RDF has a recommended XML serialization form [RDF-SYNTAX], which can be used to encode the
data model for exchange of information among applications.
RDF can use values represented according to XML schema datatypes
[XML-SCHEMA2], thus assisting the
exchange of information between RDF and other XML applications.
To facilitate operation at Internet scale, RDF is an
open-world framework that allows anyone to make statements
about any resource.
In general, it is not assumed that complete information
about any resource is available. RDF does not prevent anyone
from making assertions that are nonsensical or inconsistent
with other statements, or the world as people see it. Designers
of applications that use RDF should be aware of this and may
design their applications to tolerate incomplete or
inconsistent sources of information.
RDF uses the following key concepts:
- Graph data model
- URI-based vocabulary
- Datatypes
- Literals
- XML serialization syntax
- Expression of simple facts
- Entailment
The underlying structure of any expression in RDF 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 (defined more formally in
section 6). 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").
Each triple represents a statement of a relationship between
the things denoted by the nodes that it links. Each triple has
three parts:
- a subject,
- an object, and
- a predicate (also called a
property) that denotes a
relationship.
The direction of the arc is significant: it always points
toward the object.
The nodes of an RDF graph
are its subjects and objects.
The assertion of an RDF triple says that some relationship,
indicated by the predicate, holds between the things denoted by
subject and object of the triple. The assertion of an RDF graph
amounts to asserting all the triples in it, so the meaning of
an RDF graph is the conjunction (logical AND) of the statements
corresponding to all the triples it contains. A formal account
of the meaning of RDF graphs is given in [RDF-SEMANTICS].
A node may be a URI with optional fragment identifier (URI reference, or URIref), a literal,
or blank (having no separate form of identification).
Properties are URI references. (See [URI], section 4, for a description of URI
reference forms, noting that relative URIs are not used in an
RDF graph. See also section
6.4.)
A URI reference or literal used as a node identifies what
that node represents. A URI reference used as a predicate
identifies the relationship between the nodes it connects. A
predicate URI reference may also be a node in the graph.
A blank node is a node that is
not a URI reference or a literal. In the RDF abstract syntax, a
blank node is just a unique node that can be used in one or
more RDF statements, and has no globally distinguishing
identity.
A convention used by some linear representations of an RDF
graph to allow several statements to reference the same
unidentified resource is to use a blank node
identifier, which is a local identifier that can be
distinguished from all URIs and literals. When graphs are
merged, their blank nodes must be kept distinct if meaning is
to be preserved; this may call for re-allocation of blank node
identifiers. Note that such blank node identifiers are not part
of the RDF abstract syntax, and the representation of triples
containing blank nodes is entirely dependent on the particular
concrete syntax used.
Datatypes are used by RDF in the representation of values such
as integers, floating point numbers and dates.
RDF uses the datatype abstraction defined by XML Schema Part 2:
Datatypes [XML-SCHEMA2], and may be used with any datatype definition that conforms to this abstraction, even if not actually defined in terms of XML Schema.
A datatype mapping is a set of pairs
whose first element belongs to the lexical space of the datatype,
and the second element belongs to the value space of the datatype:
- Each member of the lexical space is paired with
(maps to) exactly one member of the value
space.
- Each member of the value space may be paired with any
number (including zero) of members of
the lexical space (lexical
representations for that value).
With one exception, the datatypes used in RDF have a
lexical space consisting of a set of
strings. The exception is rdf:XMLLiteral, whose
lexical space also includes pairs of strings and language
identifiers. The value obtained through its datatype mapping may
depend on the language identifier.
For example, the datatype mapping for the XML Schema datatype
xsd:boolean, where each member of the value space
(represented here as 'T' and 'F') has two lexical representations,
is as follows:
| Value Space |
{T, F} |
| Lexical Space |
{"0", "1", "true", "false"} |
| Datatype Mapping |
{<"true", T>, <"1", T>, <"0", F>,
<"false", F>} |
RDF predefines just one datatype rdf:XMLLiteral, used for
embedding XML in RDF (see section
5).
There is no built-in concept of numbers or dates or other common
values. Rather, RDF defers to datatypes that are defined
separately, and identified with URI references.The predefined XML Schema
datatypes [XML-SCHEMA2] are expected
to be widely used for this purpose.
Certain XML Schema built-in datatypes are not suitable for use
within RDF. For example, the
QName
datatype requires a namespace declaration to be in scope during
the mapping, and is not recommended for use in RDF.
RDF provides no mechanism for defining new datatypes. XML Schema
Datatypes [XML-SCHEMA2] provides an
extensibility framework suitable for defining new datatypes for use
in RDF.
Literals are used to identify values such as numbers and dates
by means of a lexical representation. Anything represented by a
literal could also be represented by a URI, but it is often more
convenient or intuitive to use literals.
A literal may be the object of an RDF statement, but not the
subject or the arc.
Literals may be plain or typed :
- A plain literal is a string combined
with an optional language identifier. This should be used for
plain text in a natural language. As recommended in the RDF
formal semantics [RDF-SEMANTICS], these plain literals are
self-denoting.
- A typed literal is a string, a
datatype URI and an optional language identifier. It denotes the
member of the identified datatype's value space obtained by
applying the datatype mapping to the literal string.
Continuing the example from section
3.3, the typed literals which can be defined using the XML
Schema datatype xsd:boolean are:
| Typed Literal |
Datatype Mapping |
Value |
| <xsd:boolean, "true"> |
<"true", T> |
T |
| <xsd:boolean, "1"> |
<"1", T> |
T |
| <xsd:boolean, "false"> |
<"false", F> |
F |
| <xsd:boolean, "0"> |
<"0", F> |
F |
Some simple facts indicate a relationship between
two objects.
Such a fact may be represented as an RDF triple in which the predicate
names the relationship, and the subject and object denote the two objects.
A familiar representation of such a fact might be
as a row in a table in a relational database. The table has
two columns, corresponding to the subject and the object of the
RDF triple.
The name of the table corresponds to the predicate
of the RDF triple. A further familiar representation may be as a
two place predicate
in first order logic.
Relational databases permit a table to have an arbitrary number of columns,
a row of which expresses information corresponding to a predicate in first
order logic with an arbitrary number of places. Such a row, or predicate,
has to be decomposed for representation as RDF triples. A simple form of
decomposition introduces a new blank node, corresponding to the row, and a
new triple is introduced for each cell in the row. The subject of each
triple is the new blank node, the predicate corresponds to the column name,
and object corresponds to the value in the cell. The new blank node may
also have an rdf:type property whose value corresponds
to the table name.
As an example, consider Figure 5 from the
[RDF-PRIMER]:
This information might correspond to a row in a table "STAFFADDRESSES",
with a primary key
STAFFID,
and additional columns
STREET,
STATE,
CITY and
ZIP.
Thus, a more complex fact is expressed in RDF using a
conjunction (logical-AND) of simple binary relationships. RDF does not
provide means to express negation (NOT) or disjunction (OR).
Through its use of extensible URI-based vocabularies, RDF
provides for expression of facts about arbitrary subjects; i.e.
assertions of named properties about specific named things. A URI
can be constructed for any thing that can be named, so RDF facts
can be about any such things.
The ideas on meaning and inference in RDF are underpinned by the
formal concept of
entailment, as
discussed in the RDF
semantics document [RDF-SEMANTICS].
In brief, an RDF expression A is said to
entail another RDF expression B if every possible
arrangement of things in the world that makes A true also makes B
true. On this basis, if the truth of A is presumed or demonstrated
then the truth of B can be inferred .
RDF uses URI references to identify resources and
properties. Certain URI references are reserved for use by RDF,
and should not be used in ways not supported by the RDF
specifications. Specifically, URI references with the following
leading substrings are reserved for definition by the RDF
specifications:
- http://www.w3.org/1999/02/22-rdf-syntax-ns#
(conventionally associated with namespace prefix rdf:)
- http://www.w3.org/2000/01/rdf-schema#
(conventionally associated with namespace prefix rdfs:)
Used with the RDF/XML serialization, these URI prefix
strings correspond to XML namespace names [XML-NS] associated with the RDF core
vocabulary terms.
Note: these namespace names are the same
as those used in earlier RDF documents [RDF-MS] [RDF-SCHEMA].
Vocabulary terms in the rdf:
namespace are listed in
section 5.1 of the RDF syntax specification [RDF-SYNTAX]. Some of these terms are
defined by the RDF specifications to denote specific concepts.
Others have purely syntactic purpose (e.g. rdf:ID is part of
the RDF/XML syntax) and should not be used in RDF to denote any
kind of resource.
Vocabulary terms defined in the rdfs: namespace are defined in the RDF
schema vocabulary specification [RDF-VOCABULARY].
RDF provides for XML content as a possible literal value. This
typically originates from the use of
rdf:parseType="Literal" in the RDF/XML Syntax [RDF-SYNTAX].
Such content is indicated in an RDF graph using a typed literal
whose datatype is a special built-in datatype,
rdf:XMLLiteral.
As part of the definition of this datatype, an ancillary
definition is used.
The XML document corresponding to a pair ( str,
lang ) is formed as follows:
Concatenate the five strings:
- "<rdf-wrapper xml:lang='"
- lang
- "'>"
- str
- "</rdf-wrapper>"
Encode the resulting Unicode string in UTF-8 to form the
corresponding XML document.
No escaping is applied. The choice of rdf-wrapper
is fixed but arbitrary.
The XML document corresponding to a string
str is formed as the XML document corresponding to the
pair (str, "").
Using this, the datatype rdf:XMLLiteral is
defined as follows.
- The datatype URI
- is
http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral.
- The value space
-
is the set of all XML documents that:
- Have root element tag:
<rdf-wrapper>
- Have no attributes on the root element other than
xml:lang
- are
Canonical XML [XML-C14N]
(with comments).
- The lexical space
- contains all pairs ( string, lang ) where
lang is any language identifier [RFC-3066] in lowercase, and
string is well-balanced, self-contained XML element
content [XML], for which the XML document
corresponding to the pair is a well-formed
XML document [XML] that also conforms
to XML
Namespaces [XML-NS].
- also contains all strings string which are
well-balanced, self-contained XML element content [XML], and for which the corresponding XML document
is a well-formed
XML document [XML] that also conforms
to XML
Namespaces [XML-NS].
- The mapping
- is defined as the function that maps a pair or string to the
canonical
form [XML-C14N] (with comments)
of the corresponding XML document.
Reminder: All other datatypes have a lexical space
being a set of strings, and a mapping which maps strings to
values.
Note: Not all values of this datatype are compliant
with XML 1.1 [XML 1.1]. If compliance
with XML 1.1 is desired, then only those values that are
fully
normalized according to XML 1.1 should be used.
This section defines the RDF abstract syntax. The RDF abstract
syntax is a set of triples, called the RDF graph.
This section also defines equality between RDF graphs. A
definition of equality is needed to support the RDF Test Cases [RDF-TESTS] specification.
An RDF
triple contains three components:
An RDF triple is conventionally written in the order subject,
predicate, object.
The predicate is also known as the property of the triple.
An RDF
graph is a set of RDF triples.
The nodes of an RDF graph is the set of subjects and objects of
triples in the graph.
Two RDF graphs G and G' are equal if there
is a bijection M between the nodes of the two graphs,
such that:
- M(lit)=lit for all RDF literals lit which
are nodes of either graph.
- M(uri)=uri for all RDF URI references uri
which are nodes of either graph.
- The triple ( s, p, o ) is in G if and
only if the triple ( M(s), p, M(o) ) is in
G'
With this definition, there are the same number of blank nodes in the two graphs,
and M shows how each blank node in G can be replaced with
a new blank node to give G'.
A URI reference within an RDF graph (an RDF URI reference) is a
Unicode string [UNICODE] that:
- is in Normal Form C [NFC] and
-
would produce a
valid URI character sequence (per RFC2396 [URI], sections 2.1)
when subjected to the encoding described below.
The encoding consists of:
- encoding the Unicode string as UTF-8
[RFC-2279], giving a sequence of octet values.
-
%-escaping octets that do not correspond to permitted US-ASCII characters.
The disallowed octets that must be %-escaped include all those that do not
correspond to US-ASCII characters, and the excluded characters listed in
Section 2.4 of [URI], except for the number sign (#), percent sign (%),
and the square bracket characters re-allowed in [RFC-2732].
Disallowed octets must be escaped with the URI escaping mechanism (that is, converted to %HH,
where HH is the 2-digit hexadecimal numeral corresponding to the octet value).
Two RDF URI references are equal if and only if they compare as
equal, character by character, as Unicode strings.
Editors' Note: This section is in the scope of
the TAG issue
IRIEverywhere-27.
The editors are expecting a resolution
of this issue during the last call period. This may result in updates
to this section.
Note: RDF URI references are compatible with the
anyURI datatype as defined by XML schema datatypes [XML-SCHEMA2], constrained to be an
absolute rather than a relative URI reference, and constrained to
be in Unicode Normal Form C [NFC] (for
compatibility with [CHARMOD]).
Note: RDF URI references are compatible with International Resource
Identifiers as defined by [XML
Namespaces 1.1].
Note: The restriction to absolute URI references is
found in this abstract syntax. When there is a well-defined base
URI, concrete syntaxes, such as RDF/XML, may permit relative URIs
as a shorthand for such absolute URI references.
A literal in an RDF graph
contains three components called:
The lexical form is present in all RDF literals; the language
identifier and the datatype URI may be absent from an RDF
literal.
A plain literal is one in which the datatype URI is absent.
A typed literal is one in which the datatype URI is present.
Note: Literals in which the lexical form begins with a
composing character (as defined by [CHARMOD]) are allowed however they may cause
interoperability problems, particularly with XML version 1.1 [XML 1.1].
Note: When using the language identifier, care must be
taken not to confuse language with locale. The language
identifier only relates to human language text. Presentational
issues, how to best represent typed data to the end-user, should
be addressed in end-user applications.
Two literals are equal if and only if all of the following
hold:
- The strings of the two lexical forms compare equal, character
by character.
- Either both or neither have language identifiers.
- The language identifiers of the two lexical forms compare
equal.
- Either both or neither have datatype URIs.
- The two datatype URIs, if any, compare equal, character by
character.
Note: RDF Literals are distinct and distinguishable
from RDF URI references; e.g. http://example.org as an RDF
Literal (untyped, without a language identifier) is not equal to
http://example.org as an RDF URI reference.
The datatype URI refers to a datatype. For XML Schema
built-in datatypes, URIs such as
http://www.w3.org/2001/XMLSchema#int are used. The URI
of the datatype rdf:XMLLiteral may be used.
There may be other, implementation dependent, mechanisms by which
URIs refer to datatypes.
The value associated with a typed literal is found by
applying the datatype mapping associated with the datatype URI to
the lexical form.
Exceptionally, if the datatype is rdf:XMLLiteral and the
literal has a language identifier, then the datatype mapping is
applied to the pair form by the lexical form and the language
identifier.
If the lexical form is not in
the lexical space of the datatype associated with the datatype URI,
then no literal value can be associated with the typed literal.
Such a case, while in error, is not syntacticly ill-formed.
A typed literal for which the datatype does not map the lexical
form to a value is not syntacticly ill-formed.
Note:
In application contexts, comparing the values of typed literals (see
section
6.5.2)
is usually more helpful than comparing their syntactic forms (see
section
6.5.1).
Similarly, for comparing RDF Graphs,
semantic notions of entailment (see
[RDF-SEMANTICS]) are usually
more helpful than syntactic equality (see
section
6.3).
The blank nodes in an RDF graph
are drawn from an infinite set.
This set of blank nodes, the set of all RDF URI references
and the set of all literals are pairwise disjoint.
Otherwise, this set is arbitrary.
RDF makes no reference to any internal structure of blank nodes.
RDF uses an RDF URI
Reference, which may include a fragment identifier, as a
context free identifier for a resource. RFC 2396 [URI] states that the meaning of a fragment
identifier depends on the MIME content-type of a document, i.e.
is context dependent.
These apparently conflicting views are reconciled by
considering that a URI reference in an RDF graph is treated
with respect to the MIME type application/rdf+xml [RDF-MIME-TYPE]. Given an RDF URI
reference consisting of an absolute URI and a fragment
identifier, the fragment identifer identifies the same thing
that it does in an application/rdf+xml representation of the
resource identified by the absolute URI component. Thus:
- we assume that the URI part (i.e. excluding fragment
identifier) identifies a resource, which is presumed to have
an RDF representation. So when eg:someurl#frag is used in an RDF
document, eg:someurl is taken to
designate some RDF document (even when no such document can
be retrieved).
- eg:someurl#frag means the thing
that is indicated, according to the rules of the application/rdf+xml MIME content-type as
a "fragment" or "view" of the RDF document at eg:someurl. If the document does not
exist, or cannot be retrieved, or is available only in
formats other than application/rdf+xml, then exactly what
that view may be is somewhat undetermined, but that does not
prevent use of RDF to say things about it.
- the RDF treatment of a fragment identifier allows it to
indicate a thing that is entirely external to the document,
or even to the "shared information space" known as the Web.
That is, it can be a more general idea, like some particular
car or a mythical Unicorn.
- in this way, an application/rdf+xml document acts as an
intermediary between some Web retrievable documents (itself,
at least, also any other Web retrievable URIs that it may
use, possibly including schema URIs and references to other
RDF documents), and some set of possibly abstract or non-Web
entities that the RDF may describe.
This provides a handling of URI references and their
denotation that is consistent with the RDF model theory and
usage, and also with conventional Web behavior. Note that
nothing here requires that an RDF application be able to
retrieve any representation of resources identified by the URIs
in an RDF graph.
This document contains a significant contribution from Pat
Hayes, Sergey Melnik and Patrick Stickler, under whose leadership
was developed the framework described in the RDF family of
specifications for representing datatyped values, such as integers
and dates.
The editors acknowledge valuable contributions from the
following:
Frank Manola,
Pat Hayes,
Dan Brickley,
Jos de Roo,
Dave Beckett,
Patrick Stickler,
Peter F. Patel-Schneider,
Jerome Euzenat,
Massimo Marchiori,
Tim Berners-Lee,
Dave Reynolds
and Dan Connolly.
Jeremy Carroll thanks Oreste
Signore, his host at the W3C
Office in Italy and Istituto di Scienza e Tecnologie dell'Informazione
"Alessandro Faedo", part of the Consiglio Nazionale delle Ricerche,
where Jeremy is a visiting researcher.
This document is a product of extended deliberations by the
RDFcore Working Group, whose members have included:
Art Barstow (W3C),
Dave Beckett (ILRT),
Dan Brickley (ILRT),
Dan Connolly (W3C),
Jeremy Carroll (Hewlett Packard),
Ron Daniel (Interwoven Inc),
Bill dehOra (InterX),
Jos De Roo (AGFA),
Jan Grant (ILRT),
Graham Klyne (Nine by Nine),
Frank Manola (MITRE Corporation),
Brian McBride (Hewlett Packard),
Eric Miller (W3C),
Stephen Petschulat (IBM),
Patrick Stickler (Nokia),
Aaron Swartz (HWG),
Mike Dean (BBN Technologies / Verizon),
R. V. Guha (Alpiri Inc),
Pat Hayes (IHMC),
Sergey Melnik (Stanford University) and
Martyn Horner (Profium Ltd).
This specification also draws upon an earlier RDF Model and
Syntax document edited by Ora Lassilla and Ralph Swick, and RDF
Schema edited by Dan Brickley and R. V. Guha. RDF and RDF Schema
Working Group members who contributed to this earlier work are:
Nick Arnett (Verity),
Tim Berners-Lee (W3C),
Tim Bray (Textuality),
Dan Brickley (ILRT / University of Bristol),
Walter Chang (Adobe),
Sailesh Chutani (Oracle),
Dan Connolly (W3C),
Ron Daniel (DATAFUSION),
Charles Frankston (Microsoft),
Patrick Gannon (CommerceNet),
R. V. Guha (Epinions, previously of Netscape
Communications),
Tom Hill (Apple Computer),
Arthur van Hoff (Marimba),
Renato Iannella (DSTC),
Sandeep Jain (Oracle),
Kevin Jones, (InterMind),
Emiko Kezuka (Digital Vision Laboratories),
Joe Lapp (webMethods Inc.),
Ora Lassila (Nokia Research Center),
Andrew Layman (Microsoft),
Ralph LeVan (OCLC),
John McCarthy (Lawrence Berkeley National Laboratory),
Chris McConnell (Microsoft),
Murray Maloney (Grif),
Michael Mealling (Network Solutions),
Norbert Mikula (DataChannel),
Eric Miller (OCLC),
Jim Miller (W3C, emeritus),
Frank Olken (Lawrence Berkeley National Laboratory),
Jean Paoli (Microsoft),
Sri Raghavan (Digital/Compaq),
Lisa Rein (webMethods Inc.),
Paul Resnick (University of Michigan),
Bill Roberts (KnowledgeCite),
Tsuyoshi Sakata (Digital Vision Laboratories),
Bob Schloss (IBM),
Leon Shklar (Pencom Web Works),
David Singer (IBM),
Wei (William) Song (SISU),
Neel Sundaresan (IBM),
Ralph Swick (W3C),
Naohiko Uramoto (IBM),
Charles Wicksteed (Reuters Ltd.),
Misha Wolf (Reuters Ltd.) and
Lauren Wood (SoftQuad).
9.1 Normative References
- [RDF-SYNTAX]
- RDF/XML
Syntax Specification (Revised), Dave Beckett, World Wide
Web Consortium, 8 November 2002 (work in progress). This version
of the RDF/XML Syntax Specification (Revised) is
http://www.w3.org/TR/2002/WD-rdf-syntax-grammar-20021108/. The
latest version is at http://www.w3.org/TR/rdf-syntax-grammar/.
- [RDF-SEMANTICS]
- RDF Semantics,
P. Hayes, World Wide
Web Consortium, 12 November 2002 (work in progress).
This version of the RDF Semantics is
http://www.w3.org/TR/2002/WD-rdf-mt-20021112/. The latest version
is at http://www.w3.org/TR/rdf-mt/.
- [RDF-VOCABULARY]
- RDF Vocabulary
Description Language 1.0: RDF Schema, Dan Brickley, R.V.
Guha, World Wide Web Consortium, April 2002 (work in progress).
This version of the RDF Vocabulary
Description Language is http://www.w3.org/TR/2002/WD-rdf-schema-20021112/.
The latest version is at http://www.w3.org/TR/rdf-schema/.
- [RDF-MIME-TYPE]
-
Application/rdf+xml Media Type Registration, A. Swartz,
IETF Internet Draft, March 2002 (work in progress). Version
available at
http://www.ietf.org/internet-drafts/draft-swartz-rdfcore-rdfxml-mediatype-01.txt.
- [XML]
- Extensible Markup
Language (XML) 1.0, Second Edition, T. Bray, J. Paoli,
C.M. Sperberg-McQueen and E. Maler, Editors. World Wide Web
Consortium. 6 October 2000. This version is
http://www.w3.org/TR/2000/REC-xml-20001006. The
latest version of XML is available at http://www.w3.org/TR/REC-xml.
- [XML-NS]
- Namespaces in
XML, T. Bray, D. Hollander and A. Layman, Editors.
World Wide Web Consortium. 14 January 1999. This version is
http://www.w3.org/TR/1999/REC-xml-names-19990114/.
The latest version
of Namespaces in XML is available at
http://www.w3.org/TR/REC-xml-names/.
- [RFC-2279]
- RFC 2279
- UTF-8, a transformation format of ISO 10646, F.
Yergeau, IETF, January 1998. This document is
http://www.isi.edu/in-notes/rfc2279.txt.
- [URI]
- RFC
2396 - Uniform Resource Identifiers (URI): Generic
Syntax, T. Berners-Lee, R. Fielding and L. Masinter,
IETF, August 1998. This document is
http://www.isi.edu/in-notes/rfc2396.txt.
- [HTTP]
- RFC
2616 - Hypertext Transfer Protocol -- HTTP/1.1,
R. Fielding, UC Irvine, J. Gettys, J. Mogul, H. Frystyk, L. Masinter,
P. Leach,
T. Berners-Lee,
IETF, August 1998. This document is
http://www.isi.edu/in-notes/rfc2616.txt.
- [URI-REG]
- RFC
2717 - Registration Procedures for URL Scheme Names,
R. Petke and I. King, IETF, November 1999. This document is
http://www.isi.edu/in-notes/rfc2717.txt.
- [RFC-2732]
- RFC 2732
- Format for Literal IPv6 Addresses in URL's, R. Hinden,
B. Carpenter and L. Masinter, IETF, December 1999. This document
is http://www.isi.edu/in-notes/rfc2732.txt.
- [UNICODE]
- The Unicode Standard, Version 3, The Unicode
Consortium, Addison-Wesley, 2000. ISBN 0-201-61633-5, as updated
from time to time by the publication of new versions. (See http://www.unicode.org/unicode/standard/versions/
for the latest version and additional information on versions of
the standard and of the Unicode Character Database).
- [NFC]
- Unicode
Normalization Forms, Unicode Standard Annex #15, Mark
Davis, Martin Dürst. (See http://www.unicode.org/unicode/reports/tr15/
for the latest version).
- [RFC-3066]
- RFC 3066
- Tags for the Identification of Languages, H.
Alvestrand, IETF, January 2001. This document is
http://www.isi.edu/in-notes/rfc3066.txt.
- [XML-C14N]
- Canonical
XML. J. Boyer. W3C Recommendation, March 2001.
- Available at http://www.w3.org/TR/2001/REC-xml-c14n-20010315
- Available at http://www.ietf.org/rfc/rfc3076.txt
- [XML-SCHEMA2]
- XML Schema
Part 2: Datatypes - W3C Recommendation, World Wide Web
Consortium, 2 May 2001.
9.2 Informational
References
- [RDF-TESTS]
- RDF Test
Cases, Jan Grant and Dave Beckett, Editors. Work in
progress. World Wide Web Consortium, 29 April 2002. This version
of the RDF Test Cases is
http://www.w3.org/TR/2002/WD-rdf-testcases-20021112/.
The latest version of the RDF Test Cases is at http://www.w3.org/TR/rdf-testcases/.
- [RDF-PRIMER]
- RDF
Primer, F. Manola, E. Miller, Editors, World Wide Web
Consortium W3C Working Draft, work in progress, 26 April 2002.
This version of the RDF Primer is
http://www.w3.org/TR/2002/WD-rdf-primer-20020426/. The latest version of the RDF
Primer is at http://www.w3.org/TR/rdf-primer/.
- [CHARMOD]
- Character Model
for the World Wide Web 1.0, M. Dürst, F. Yergeau,
R. Ishida, M. Wolf, A. Freytag, T Texin, Editors, World Wide Web
Consortium Working Draft, work in progress, 20 February 2002.
This version of the Character Model is
http://www.w3.org/TR/2002/WD-charmod-20020220/. The latest version of the Character
Model is at http://www.w3.org/TR/charmod/.
- [XML-1.1]
- Extensible Markup
Language (XML) 1.1, John Cowan, Editor. World Wide Web
Consortium Working Draft 25 April 2002. (Work in
progress)
- [XML-NAMESPACES-1.1]
- Namespaces
in XML 1.1, Tim Bray, Dave Hollander, Andrew Layman,
Richard Tobin, Editors. World Wide Web Consortium Working Draft 5
September 2002. (Work in progress)
- [XML-INFOSET]
- XML
Information Set, John Cowan and Richard Tobin, W3C
Recommendation, 24 October 2001. This document is
http://www.w3.org/TR/xml-infoset/.
- [OWL]
- OWL Web
Ontology Language 1.0 Reference, Mike Dean, Dan Connolly,
Frank van Harmelen, James Hendler, Ian Horrocks, Deborah L.
McGuinness, Peter F. Patel-Schneider, and Lynn Andrea Stein. W3C
Working Draft 29 July 2002. Latest version is available at http://www.w3.org/TR/owl-ref/.
- [RDF-MS]
- Resource
Description Framework (RDF) Model and Syntax
Specification, O. Lassila and R. Swick, Editors. World
Wide Web Consortium. 22 February 1999. This version is
http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/. The latest version of RDF
M&S is available at
http://www.w3.org/TR/REC-rdf-syntax/.
- [RDF-SCHEMA]
-
Resource
Description Framework (RDF) Schema Specification 1.0, Dan
Brickley and R. V. Guha, W3C Candidate Recommendation, 27 March
2000. This document is http://www.w3.org/TR/2000/CR-rdf-schema-20000327/.
We divide these into substantive and editorial.
The substantive changes also list consquential editorials changes.
Editorial changes are those which do not result in any change in
the meaning of an RDF document or the behaviour of an RDF application.
-
pfps-14
- Deleted
section 4 about social meaning. Also removed
previous
section 2.2.8 ("A Basis for Binding Agreements") as
this also related to social meaning. Also: removed mention in
section
3.3. Datatypes about the defining authority of a datatype URI. Small
consequential changes in abstract and introduction and
bulleted list at start of section 2.2.
-
macgregor-01,
macgregor-02
- These issues, about distinguishing asserted and
non-asserted statements and propositional attitudes, are
addressed by the removal of
section 4,
which raised doubts
about their inclusion in RDF.
- Polishing
- Minor changes in bulleted list at start of section 2.2
- Minor fix to reference in note of section 2.2.1
- Two word simplification in bullet list at start of section 3
- Renumbering
- Renumbered previous
section 3.7
to
section 4, as it doesn't
really seem to belong in "Concepts" (and to minimize
renumbering of the document).
- Namespace name
-
Also changed "namespace URI" to
"namespace name", to be more consistent with XML namespace
termonology.
-
williams-01
- Rework text in section 3.2 to be more consistent with
view of URIs as nodes (rather than node labels). Included
revised introduction of node concept in section 3.1. Used
some of
Pat Hayes' suggested text in section 3.1. Also some
impact on rewording in section 2.2.6. Some further small
reworking of sections 3.1, 3.2 in response to RDFcore mailing
list comments.
- predicate
or property
- Section 3.1, replace use of "property" by "predicate".
Similarly, other uses throughout the document. The term
"property" still appears, but "predicate" is now used as the
lead term. The naming convention is that
predicate, node, triple are
preferred as syntactic terms; property, resource, statement are preferred
as semantic terms.
- Related to
pfps-15 on the Primer
- Deleted section
2.2.7 (which didn't say anything not
already covered by section 2.2.6), and
revised title and wording
of section 2.2.6.
-
pfps-16
-
Removed one false sentence from section 3.5 concerning expressive power; and consequentially
[SOWA] reference.
-
pfps-22,
pfps-23
- Revised text in section 4 to clarify role of RDF(S)
vocabulary. Also changed term "URI" to "URI reference".
- FragID clarifications
- Reworked text in section 7 to clarify
its intent, and
added note that retrieval of resource representation is not
required . This in response to last-call comments from
Stuart
Williams and
Massimo Marchiori.
