ISO/IEC 13250-3:2013

INTERNATIONAL ISO/IEC
STANDARD 13250-3
Second edition
2013-11-01
Information technology — Topic Maps —
Part 3:
XML syntax
Technologies de l'information — Plans relatifs à des sujets —
Partie 3: Syntaxe XML
Reference number
©
ISO/IEC 2013
©  ISO/IEC 2013
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ii © ISO/IEC 2013 – All rights reserved

Page
Contents
Foreword. iv
Introduction.  v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 1
4 Syntax definition. 2
4.1 About the syntax. 2
4.2 Deserialization. 2
4.3 Common syntactical constructs. 2
4.3.1 Common declarations. 2
4.3.2 The reifier attribute. 3
reifier
4.3.3 The element. 3
4.3.4 The href attribute. 3
4.3.5 Creating IRIs from strings. 3
topicMap
4.4 The element. 4
topic
4.5 The element. 4
itemIdentity
4.6 The element. 4
subjectLocator
4.7 The element. 4
subjectIdentifier
4.8 The element. 5
instanceOf
4.9 The element. 5
name
4.10 The element. 5
value
4.11 The element. 6
variant
4.12 The element. 6
scope
4.13 The element. 6
type
4.14 The element. 6
occurrence
4.15 The element. 6
resourceData
4.16 The element. 7
4.16.1 General. 7
4.16.2 Deserialization. 7
4.16.3 Canonicalizing embedded XML. 7
resourceRef
4.17 The element. 7
association
4.18 The element. 8
role
4.19 The element. 8
topicRef
4.20 The element. 8
subjectIdentifierRef
4.21 The element. 8
subjectLocatorRef
4.22 The element. 9
mergeMap
4.23 The element. 9
5 Conformance. 9
Annex A (normative) A RELAX-NG schema for XTM 2.1. 10
Annex B (informative) The XTM 2.1 DTD. 12
Annex C (informative) A W3C XML Schema schema for XTM 2.1. 16
Annex D (informative) Differences from XTM 2.0 to XTM 1.0. 21
Annex E (informative) Differences from XTM 2.1 to XTM 2.0. 22
Annex F (informative) Subject identifiers for defined terms. 23
Bibliography. 24
© ISO/IEC 2013 – All rights reserved
iii
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 13250-3 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 34, Document description and processing languages.
This second edition cancels and replaces the first edition (ISO/IEC 13250-3:2007), which has been technically
revised. ISO/IEC 13250-3 is part of a multi-part standard. The complete series will cancel and replace
ISO/IEC 13250:2003.
ISO/IEC 13250 consists of the following parts, under the general title Information technology — Topic Maps:
— Part 2: Data model
— Part 3: XML syntax
— Part 4: Canonicalization
— Part 5: Reference model
— Part 6: Compact syntax
iv © ISO/IEC 2013 – All rights reserved

Introduction
XTM (XML Topic Maps) 2.1 is a syntax for the interchange of Topic Maps. The syntax is not designed to be extended
or modified. Ease of human authoring was not prioritized during the design of XTM, and consequently it is not
recommended to edit the syntax directly.
This part of ISO/IEC 13250 should be read in conjunction with [ISO/IEC 13250-2] since the interpretation of the XTM
syntax is defined through a mapping from the syntax to the data model there defined.
XTM 2.1 is a revision of the XTM 2.0 syntax defined in [ISO/IEC 13250-3:2007]. A description of the differences
between the two versions can be found in Annex E.
© ISO/IEC 2013 – All rights reserved
v
© ISO/IEC 2013 – All rights reserved
vi
INTERNATIONAL STANDARD ISO/IEC 13250-3:2013(E)
Information technology — Topic Maps —
Part 3:
XML syntax
1 Scope
This part of ISO/IEC 13250 defines an XML-based interchange syntax for Topic Maps, which can be used to
interchange instances of the data model defined in [ISO/IEC 13250-2]. It also defines a mapping from the interchange
syntax to the data model. The syntax is defined with a RELAX-NG schema, and more precision is provided through
the mapping to the data model, which effectively also defines the interpretation of the syntax.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
NOTE Each of the following documents has a unique identifier that is used to cite the document in the text. The unique
identifier consists of the part of the reference up to the first comma.
ISO/IEC 13250-2, Information technology — Topic Maps — Data Model
W3C XML, Extensible Markup Language (XML) 1.1 (Second Edition), W3C Recommendation, 29 September 2006,
available at
W3C XML-Names, Namespaces in XML, W3C Recommendation, 14 January 1999, available at

W3C XML-Infoset, XML Information Set (Second Edition), W3C Recommendation, 4 February 2004, available at

W3C Canonical XML, Canonical XML Version 1.0, W3C Recommendation, 15 March 2001, available at

ISO/IEC 19757-2, Information technology — Document Schema Definition Languages (DSDL) — Part 2: Grammar-
based validation — RELAX NG
IETF RFC 3986, Uniform Resource Identifiers (URI): Generic Syntax, Internet Standards Track Specification, January
2005, available at
IETF RFC 3987, Internationalized Resource Identifiers (IRIs), Internet Standards Track Specification, January 2005,
available at
3 Terms and definitions
For the purposes of this part of ISO/IEC 13250, the following terms and definitions apply.
3.1
XTM
the syntax defined in this part of ISO/IEC 13250
© ISO/IEC 2013 – All rights reserved
4 Syntax definition
4.1 About the syntax
The acronym XTM is often used to refer to the syntax defined in this part of ISO/IEC 13250. Its full name is XML Topic
http://www.topicmaps.org/xtm/
Maps. The namespace for the XTM syntax is .
An XTM document is an XML document that conforms to the XTM syntax. This clause defines the syntax of XTM
documents using a RELAX-NG schema in compact syntax [ISO/IEC 19757-2], and their semantics using prose
describing the mapping from XTM documents to [ISO/IEC 13250-2]. The full schema can be found in Annex A, a
DTD in Annex B, and a W3C XML Schema in Annex C.
4.2 Deserialization
The process of exporting Topic Maps from an implementation's internal representation of the data model to an
instance of a Topic Maps syntax is known as serialization. The opposite process, deserialization, is the process of
building an instance of an implementation's internal representation of the data model from an instance of a Topic
Maps syntax.
This clause defines how instances of the XTM syntax are deserialized into instances of the data model defined in
[ISO/IEC 13250-2]. Serialization is only implicitly defined, but implementations should guarantee that for any data
model instance the XTM serialization produced by the implementation should when deserialized to a new data model
instance produce one that
...