Status: Published

Updated: 10 May 2012

Previous Version: 28 March 2011


This document describes the MADS/RDF (Metadata Authority Description Schema in RDF) vocabulary, a data model for authority and vocabulary data used within the library and information science (LIS) community, which is inclusive of museums, archives, and other cultural institutions.  It is presented as an OWL ontology.

MADS/RDF is a knowledge organization system (KOS) designed for use with controlled values for names (personal, corporate, geographic, etc.), thesauri, taxonomies, subject heading systems, and other controlled value lists.  It is closely related to SKOS, the Simple Knowledge Organization System and a widely supported and adopted RDF vocabulary.  Given the close relationship between the aim of MADS/RDF and the aim of SKOS, the MADS ontology has been fully mapped to SKOS.  

Unlike SKOS, however, which is very broad in its application, MADS/RDF is designed specifically to support authority data as used by and needed in the LIS community and its technology systems.  For example, MADS/RDF provides a means to record data from the Machine Readable Cataloging (MARC) Authorities format in RDF for use in semantic applications and Linked Data projects.

MADS/RDF is designed to support the description of cultural and bibliographic resources.  Data described using MADS/RDF, therefore, assists with identifying and annotating bibliographic and cultural resources.   MADS/RDF is not focused on the description of Real World Objects.  Although a MADS/RDF description may contain information specific to the Real World Object associated with the MADS/RDF authoritative label, the MADS/RDF ontology distinguishes between these two entities – the RWO and the Authority.

Status of This Document

This document is intended for those designing and implementing LIS technology systems.  It is assumed the reader is familiar with MADS/XML, Resource Description Framework (RDF) for information modeling, and the SKOS/RDF vocabulary.

Comments are encouraged and welcome.  The MODS listserv ( ), which is a public listserv with publicly available archives managed by LC, is the preferred forum for feedback.  MADS/XML is maintained as part of the community work on MODS (Metadata Object Description Schema) ( ) and coordinated by the MODS Editorial Committee.

This document is preceded by one dated 28 March 2011.  Changes include, but are not limited to:

  1. Addition of new MADS Type, madsrdf:Language.  

  2. Note to record change permitting the use of rdf:Seq with madsrdf:componentList and madsrdf:elementList.

Table of Contents

1 Introduction

1.1 Ontology and Namespaces

A MADS/RDF namespace document, which provides a human-accessible list of MADS/RDF classes and properties, is accessible at:

MADS/RDF is modeled as an OWL Full ontology.  It is available at:

The MADS/RDF namespace is:


Other namespaces and prefixes used in this document or defined in the ontology are:

Namespace Prefix

Namespace URI







1.2 Background

MADS/RDF provides a means to represent the detailed information embedded in common LIS authority records.  Although SKOS has proven a robust and very flexible data model, it does not capture the level of detail in LIS authority and vocabulary data.  

The Library of Congress has experience representing authority data in SKOS/RDF since early 2009, before the SKOS specification was a formal W3C recommendation.  LC was an early adopter of SKOS.  SKOS was employed in its Linked Data service, ID.LOC.GOV, which made the entire LC Subject Headings (LCSH) file available in SKOS/RDF format.  This enriching experience has, immediately after launch and over time, revealed some of the challenges involved in representing more complex authority data purely in SKOS.  One of the larger issues quickly brought to LC's attention by users of the data was: LC is not passing on useful data in its (MARC) authority records because SKOS does not provide a way to capture the information, such as the multiple components, and their types, of pre-coordinated subject headings.  This is in no way a fault of SKOS.  SKOS was designed to be “a common data model for sharing and linking knowledge organization systems via the Web.”  It achieves its aim admirably.  Part of SKOS's success, however, comes from abstracting or generalizing organization systems, thereby creating a common set of data elements (Classes and Properties) that can be supported by a wide range of users and for an equally wide range of thesauri, controlled lists, subject heading systems and taxonomies.  Indeed, SKOS accommodates LIS authority data very nicely after the data has been somewhat generalized.

MADS/RDF is designed to complement SKOS and, as such, is formally mapped to the SKOS/RDF vocabulary.  This mapping, which can be used for inferencing purposes, facilitates data exchange between a MADS/RDF user and a SKOS user.  Nevertheless, MADS/RDF is a more specifically defined data model to represent the complexities of authority, vocabulary, and thesauri data.  In part because MADS/RDF derives, ultimately, from the MARC Authority format, it is expected that MADS/RDF will be of greatest interest to the LIS community, though it may also be of interest to non-library applications.  It provides a means to not only capture information regularly found in LIS authority records but also represent authority data as it has come to be expected by those working in the LIS community.  

MADS/RDF does not capture the nuances and rules for the use and creation of labels – the actual headings themselves - nor is it designed for this purpose.  For example, the rules guiding the creation of a pre-coordinated LC Subject Heading label are beyond the scope of MADS/RDF, though MADS/RDF might be used to capture the information needed to create a pre-coordinated label.  MADS/RDF avoids, wherever possible, instituting a condition or restriction not shared by most LIS knowledge organization systems.

1.3 Some Terminology

Authority (also Authoritative form):  a concept (resource) with a controlled label.

Deprecated-authority (also Deprecated form):  a former Authoritative form.  

Label - the lexical string that is the primary focus of an Authority, Variant, or Deprecated-authority description.  The Labels of these resources are or were once controlled, meaning they were carefully curated to ensure they met some standard within the knowledge organization system.  This is the closest functional equivalent to what is commonly understood to in LIS to be a “heading.”

MARC 21 Authority format: currently the primary carrier for authority data used within the LIS community.  

Description:  Used throughout the current document to describe the compilation of facts about something or, especially in the case of the present document and topic, the collection of triple statements about an authority, variant, or deprecated-authority.  From a purely RDF view point, a “description” should be viewed as a type of (sub-)graph.  This is the closest functional equivalent to what is commonly understood to be a LIS “record.”

Variant (also Variant form):  a resource that represents the alternate form of an authoritative label.

1.4 Primary Design Goals

1.4.1  Support the individual components of pre-coordinated subject labels, hierarchical geographic labels, and name/title labels

Authoritative labels may be the concatenation of two or more labels, each of which may exist as an independent authority description with its own authoritative label.  These labels are common in LIS authority data.  Labels that are the concatenation of a Name and a Title - such as “Morrison, Toni.  Beloved.” - are of a madsrdf:NameTitle type in MADS/RDF.  “Morrison, Toni” is a controlled Name label and therefore has a distinct description, the URI of which may be used in other Authority descriptions.  A Hierarchical Geographic label, known in MADS/RDF as a madsrdf:HierarchicalGeographic, is the concatenation of two or more geographic names, such as “United States--New Jersey--Essex--Montclair,” which comprises a country, state, county, and city.  A pre-coordinated subject label, known in MADS/RDF as a madsrdf:ComplexSubject, is the concatenation of two or more simple subject labels, each of which represent individual concepts, such as “United States--History--Civil War, 1861-1865,” which comprises geographic, topic, and temporal concepts.   This is covered in more detail below, in section 2.2.

1.4.2  Interoperate with SKOS

MADS/RDF is mapped to SKOS, providing a path to full interoperability of resources described in MADS/RDF to a broad standard.  Although the details are in the OWL ontology definition, the mapping essentially makes SKOS Classes and Properties parent Classes and Properties of MADS/RDF Classes and Properties.  For example, a madsrdf:Authority is a sub-class of skos:Concept. A madsrdf:authoritativeLabel, for example, is a sub-property of skos:prefLabel.

1.4.3  Support LIS authority types

Although LIS authority labels identify concepts, it is also common practice in LIS to identify authority types more granularly.  For example, a label might represent a personal name, corporate name, title, name/title, geographic area, temporal concept, etc. These are expressed as sub-classes of madsrdf:SimpleType and madsrdf:ComplexType which indicate single and concatenated labels, respectively.  Most of the aforementioned types, especially the madsrdf:SimpleType types, were already defined in MADS/XML.  This is covered in more detail below, in section 2.2.

1.4.4   Use MADS/XML as the basis for MADS/RDF

MADS/XML ( ) provided a solid foundation for MADS/RDF.  MADS/XML, which “is a MARC 21-compatible XML format” for MARC authority data, already provided support for complex subject labels and other specific authority types.   For those familiar with MADS/XML, MADS/RDF can accommodate everything in the MADS/XML schema.  MADS/RDF required a few additions:  these range from new authority types to usage clarification and codification rules.  The names of some MADS/XML elements, attributes, and attribute values were altered to clarify the semantics in MADS/RDF.  All MADS/XML relationships in MADS/RDF have been modeled as object properties.

1.4.5  Support authority descriptions and labels

With 1.4.6 and 1.4.7 following, MADS/RDF descriptions might be madsrdf:Authority, or madsrdf:Variant and/or madsrdf:DeprecatedAuthority types.  madsrdf:Authority types represent authoritative resources and concepts, the labels of which are actively controlled.  In most cases, these will be identified as first-class resources (for Linked Data, for instance, by using HTTP URIs).  This is covered in more detail below, in section 2.1.

1.4.6  Support variant descriptions and labels

madsrdf:Variant types are variant forms of authoritative resources.  They are disjoint with madsrdf:Authority types.  It is expected that most madsrdf:Variant resources will be identified as blank nodes (i.e., no http URIs).  They can be associated with a madsrdf:Authority description via the madsrdf:hasVariant property.  The labels of a madsrdf:Variant type is identified with the madsrdf:variantLabel property.

1.4.7  Support deprecated-authority descriptions and labels

madsrdf:DeprecatedAuthority types indicate that a resource once considered authoritative, and very likely once a madsrdf:Authority, is no longer authoritative.  madsrdf:DeprecatedAuthority types are disjoint with madsrdf:Authority types, but not madsrdf:Variant types.  A madsrdf:DeprecatedAuthority resource indicates a deprecated label.  The labels of a madsrdf:DeprecatedAuthority type can be identified with the madsrdf:deprecatedLabel property.  Although this might suggest a labeling conflict, it is expected that a madsrdf:Variant will have a madsrdf:variantLabel.   madsrdf:DeprecatedAuthority has no mapping to SKOS/RDF.

1.4.8  Support the parts of labels

MADS/XML supports the parts of labels, such as the nonSort aspect of a Title authority or the givenName of the Name authority.  These are fully represented in MADS/RDF with a few semantic alterations and a few additions.   This is covered in more detail below, in section 2.5.

1.5 Examples

Theses examples illustrate the application of the ontology to describe concepts, and their labels, form the Library of Congress maintained files for names (NAF) and subjects (LCSH).

Authority ComplexSubject sh2007010620 RDF/XML Ntriples Turtle
Authority ComplexSubject sh85068030 RDF/XML Ntriples Turtle
Authority NameTitle n00000707 RDF/XML Ntriples Turtle
Authority ComplexSubject sh85099085 RDF/XML Ntriples Turtle
Authority NameTitle sh93004675 RDF/XML Ntriples Turtle
Authority NameTitle n00039722 RDF/XML Ntriples Turtle
Authority Title sh96011928 RDF/XML Ntriples Turtle
Authority Temporal sh2002012470 RDF/XML Ntriples Turtle
Authority ConferenceName n00037993 RDF/XML Ntriples Turtle
Authority Topic sh85017405 RDF/XML Ntriples Turtle
Authority PersonalName n50048460 RDF/XML Ntriples Turtle
Authority PersonalName n00009201 RDF/XML Ntriples Turtle
Authority NameTitle n00009202 RDF/XML Ntriples Turtle
Authority Geographic sh85090955 RDF/XML Ntriples Turtle
Authority Geographic sh85072887 RDF/XML Ntriples Turtle
Authority ComplexSubject sh2010003666 RDF/XML Ntriples Turtle
Authority GenreForm sh99001636 RDF/XML Ntriples Turtle
Authority ComplexSubject sh2008116061 RDF/XML Ntriples Turtle
Variant ComplexSubject sh2010100099 RDF/XML Ntriples Turtle
Variant ComplexSubject sh85120945 RDF/XML Ntriples Turtle
Authority ComplexSubject sh2010002339 RDF/XML Ntriples Turtle
Authority ComplexSubject sh2010002340 RDF/XML Ntriples Turtle
Variant GenreForm sh2002012502 RDF/XML Ntriples Turtle
Authority GenreForm sh2010004769 RDF/XML Ntriples Turtle
Authority GenreForm sh2010004770 RDF/XML Ntriples Turtle
Authority PersonalName oca08651008 RDF/XML Ntriples Turtle

2 MADS/RDF Classes

What follows is a description of the major Classes of the MADS/RDF ontology.  Brief discussion of the minor classes – such as madsrdf:Identifier, madsrdf:Affiliation, madsrdf:AffiliationAddress, and madsrdf:Source – will be incorporated at a later date.

2.1 madsrdf:Authority, madsrdf:Variant, and madsrdf:DeprecatedAuthority

madsrdf:Authority is a sub-class of skos:Concept.  A madsrdf:Authority, like a skos:Concept, “can be viewed as an idea or notion; a unit of thought.”  It is no more specific about what type of idea, notion, or unit of thought is being described.  A madsrdf:Authority represents a resource to be used in the dsecription of bibliographic or cultural objects; it is not a Real World Object.  A madsrdf:Authority description may be part of a madsrdf:MADSScheme or madsrdf:MADSCollection, both of which serve to aggregate madsrdf:Authority descriptions.  

Although an instance of a madsrdf:Variant is a resource and may be further identified as a specific MADSType (see below), it does not represent an authoritative label within the knowledge organization system.  madsrdf:Variant is disjoint with madsrdf:Authority.  In most cases, madsrdf:Variant descriptions are, and will be, represented as a blank node (i.e. not with HTTP URIs).  madsrdf:Variant, which is associated with a madsrdf:Authority through the madsrdf:hasVariant object property, is a sub-class of skosxl:Label.

Given the organic nature of a KOS, madsrdf:DeprecatedAuthority provides a means to identify a once-authoritative, but no longer authoritative, resource.  madsrdf:DeprecatedAuthority is disjoint with madsrdf:Authority, but not with madsrdf:Variant.  There is no mapping for madsrdf:DeprecatedAuthority to SKOS/RDF.  

2.2 madsrdf:MADSType

madsrdf:MADSType is an umbrella class.  It has two sub-classes:  madsrdf:ComplexType and madsrdf:SimpleType.  This organization exists primarily for inferencing purposes.  It is expected a user will identify a madsrdf:Authority, madsrdf:Variant, or madsrdf:DeprecatedAuthority description with one of the many sub-classes of madsrdf:ComplexType or madsrdf:SimpleType.

madsrdf:SimpleType is a resource with a label constituting a single word or phrase.  There are 23 sub-classes in total, ranging from madsrdf:Topic or madsrdf:GenreForm to madsrdf:City or madsrdf:ExtraterrestialArea.  One subclass, madsrdf:Name, also has 4 sub-classes: madsrdf:PersonalName, madsrdf:CorporateName, madsrdf:ConferenceName, madsrdf:FamilyName.  Most of these 23 subclasses are defined in MADS/XML.  

madsrdf:ComplexType is used to describe a resource with a label that is the concatenation of labels from two or more Authority descriptions or two or more Variant descriptions or some combination of Authority and Variant descriptions, each of a madsrdf:SimpleType.  madsrdf:ComplexType has three sub-classes:  madsrdf:NameTitle, madsrdf:HierarchicalGeographic, and madsrdf:ComplexSubject.

The label of a madsrdf:NameTitle resource is the concatenation of a label of a madsrdf:Name description and the label of a madsrdf:Title description.  Both description types (madsrdf:Name and madsrdf:Title) are of madsrdf:SimpleType types.  

Example: NameTitle Authority

  <madsrdf:NameTitle rdf:about="ex:Herman,_Jerry,_1933-_Hello,_Dolly!">
    <rdf:type rdf:resource=""/>
    <madsrdf:authoritativeLabel>Herman, Jerry, 1933- Hello, Dolly!</madsrdf:authoritativeLabel>
    <madsrdf:componentList rdf:parseType="Collection">
      <madsrdf:PersonalName rdf:nodeID="aHerman-Jerry-1933-">
        <rdf:type rdf:resource=""/>
        <madsrdf:authoritativeLabel>Herman, Jerry, 1933-</madsrdf:authoritativeLabel>
        <madsrdf:elementList rdf:parseType="Collection">
            <madsrdf:elementValue>Herman, Jerry,</madsrdf:elementValue>
      <madsrdf:Title rdf:nodeID="aHello-Dolly">
        <rdf:type rdf:resource=""/>
        <madsrdf:authoritativeLabel>Hello, Dolly!</madsrdf:authoritativeLabel>
        <madsrdf:elementList rdf:parseType="Collection">
            <madsrdf:elementValue>Hello, Dolly!</madsrdf:elementValue>
@prefix madsrdf: <>.
@prefix rdf: <>.
<ex:Herman,_Jerry,_1933-_Hello,_Dolly!> madsrdf:authoritativeLabel "Herman, Jerry, 1933- Hello, Dolly!";
  madsrdf:componentList (_:aHerman-Jerry-1933- _:aHello-Dolly);
  a madsrdf:Authority,
_:aHello-Dolly madsrdf:authoritativeLabel "Hello, Dolly!";
  madsrdf:elementList (_:bnode447719488);
  a madsrdf:Authority,
_:aHerman-Jerry-1933- madsrdf:authoritativeLabel "Herman, Jerry, 1933-";
  madsrdf:elementList (_:bnode104199680 _:bnode1680267008);
  a madsrdf:Authority,
_:bnode104199680 madsrdf:elementValue "Herman, Jerry,";
  a madsrdf:FullNameElement.
_:bnode1680267008 madsrdf:elementValue "1933-";
  a madsrdf:DateNameElement.
_:bnode447719488 madsrdf:elementValue "Hello, Dolly!";
  a madsrdf:TitleElement.
<ex:Herman,_Jerry,_1933-_Hello,_Dolly!> <> <>.
<ex:Herman,_Jerry,_1933-_Hello,_Dolly!> <> <>.
<ex:Herman,_Jerry,_1933-_Hello,_Dolly!> <> "Herman, Jerry, 1933- Hello, Dolly!".
_:aHerman-Jerry-1933- <> <>.
_:aHerman-Jerry-1933- <> <>.
_:aHerman-Jerry-1933- <> "Herman, Jerry, 1933-".
_:bnode104199680 <> <>.
_:bnode104199680 <> "Herman, Jerry,".
_:bnode622919744 <> _:bnode104199680.
_:bnode622919744 <> _:bnode1161546944.
_:bnode1680267008 <> <>.
_:bnode1680267008 <> "1933-".
_:bnode1161546944 <> _:bnode1680267008.
_:bnode1161546944 <> <>.
_:aHerman-Jerry-1933- <> _:bnode622919744.
_:bnode2115887360 <> _:aHerman-Jerry-1933-.
_:bnode2115887360 <> _:bnode539820032.
_:aHello-Dolly <> <>.
_:aHello-Dolly <> <>.
_:aHello-Dolly <> "Hello, Dolly!".
_:bnode447719488 <> <>.
_:bnode447719488 <> "Hello, Dolly!".
_:bnode71000576 <> _:bnode447719488.
_:bnode71000576 <> <>.
_:aHello-Dolly <> _:bnode71000576.
_:bnode539820032 <> _:aHello-Dolly.
_:bnode539820032 <> <>.
<ex:Herman,_Jerry,_1933-_Hello,_Dolly!> <> _:bnode2115887360.

A madsrdf:HierarchicalGeographic indicates that its label is the concatenation of labels from a sequence of madsrdf:Geographic types taken from one of the madsrdf:Geographic sub-classes such as madsrdf:City, madsrdf:Country, madsrdf:State, madsrdf:Region, madsrdf:Area, etc.  The madsrdf:Geographic resources that constitute the madsrdf:HierarchicalGeographic should have a broader to narrower hierarchical relationship between them.

Example: HierarchicalGeographic Authority

  <madsrdf:Authority rdf:about="ex:United_States--New_Jersey--Essex--Montclair">
    <rdf:type rdf:resource=""/>
    <madsrdf:authoritativeLabel>United States--New Jersey--Essex--Montclair</madsrdf:authoritativeLabel>
    <madsrdf:componentList rdf:parseType="Collection">
      <madsrdf:Country rdf:resource="ex:United_States"/>
      <madsrdf:State rdf:resource="ex:New_Jersey"/>
      <madsrdf:County rdf:resource="ex:Essex"/>
      <madsrdf:City rdf:resource="ex:Montclair"/>
@prefix madsrdf: <>.
@prefix rdf: <>.
<ex:United_States--New_Jersey--Essex--Montclair> madsrdf:authoritativeLabel "United States--New Jersey--Essex--Montclair";
  madsrdf:componentList (_:bnode2070340096 _:bnode1032899968 _:bnode1041980288 _:bnode2079420416);
  a madsrdf:Authority,
_:bnode1032899968 a madsrdf:State.
_:bnode1041980288 a madsrdf:County.
_:bnode2070340096 a madsrdf:Country.
_:bnode2079420416 a madsrdf:City.
<ex:United_States--New_Jersey--Essex--Montclair> <> <>.
<ex:United_States--New_Jersey--Essex--Montclair> <> <>.
<ex:United_States--New_Jersey--Essex--Montclair> <> "United States--New Jersey--Essex--Montclair".
_:bnode2070340096 <> <>.
_:bnode362151936 <> _:bnode2070340096.
_:bnode362151936 <> _:bnode1551620032.
_:bnode1032899968 <> <>.
_:bnode1551620032 <> _:bnode1032899968.
_:bnode1551620032 <> _:bnode4540160.
_:bnode1041980288 <> <>.
_:bnode4540160 <> _:bnode1041980288.
_:bnode4540160 <> _:bnode1560700352.
_:bnode2079420416 <> <>.
_:bnode1560700352 <> _:bnode2079420416.
_:bnode1560700352 <> <>.
<ex:United_States--New_Jersey--Essex--Montclair> <> _:bnode362151936.


The label of a madsrdf:ComplexSubject is the concatenation of labels from two or more madsrdf:SimpleType descriptions, except that the combination of madsrdf:SimpleType labels for the madsrdf:ComplexSubject does not meet the conditions to be the label of a madsrdf:NameTitle resource or madsrdf:HierarchicalGeographic resource.

Example: ComplexSubject Authority

  <madsrdf:Authority rdf:about="ex:United_States--History--Civil_War,_1861-1865">
    <rdf:type rdf:resource=""/>
    <madsrdf:authoritativeLabel>United States--History--Civil War, 1861-1865</madsrdf:authoritativeLabel>
    <madsrdf:componentList rdf:parseType="Collection">
      <madsrdf:Geographic rdf:about="ex:United_States"/>
      <madsrdf:Topic rdf:about="ex:History"/>
      <madsrdf:Temporal rdf:about="ex:Civil_War,_1861-1865"/>
@prefix madsrdf: <>.
@prefix rdf: <>.
<ex:Civil_War,_1861-1865> a madsrdf:Temporal.
<ex:History> a madsrdf:Topic.
<ex:United_States> a madsrdf:Geographic.
<ex:United_States--History--Civil_War,_1861-1865> madsrdf:authoritativeLabel "United States--History--Civil War, 1861-1865";
  madsrdf:componentList (<ex:United_States> <ex:History> <ex:Civil_War,_1861-1865>);
  a madsrdf:Authority,
<ex:United_States--History--Civil_War,_1861-1865> <> <>.
<ex:United_States--History--Civil_War,_1861-1865> <> <>.
<ex:United_States--History--Civil_War,_1861-1865> <> "United States--History--Civil War, 1861-1865".
<ex:United_States> <> <>.
_:bnode567502528 <> <ex:United_States>.
_:bnode567502528 <> _:bnode1590477440.
<ex:History> <> <>.
_:bnode1590477440 <> <ex:History>.
_:bnode1590477440 <> _:bnode1690296832.
<ex:Civil_War,_1861-1865> <> <>.
_:bnode1690296832 <> <ex:Civil_War,_1861-1865>.
_:bnode1690296832 <> <>.
<ex:United_States--History--Civil_War,_1861-1865> <> _:bnode567502528.

A madsrdf:ComplexType will have a madsrdf:componentList, which organizes madsrdf:SimpleType resources whose labels are represented in the madsrdf:ComplexType's label.  madsrdf:componentList has a range of rdf:List or rdf:Seq.  Although somewhat cumbersome, rdf:List not only serves to order the list components (the madsrdf:SimpleType descriptions) but also provides a way to establish the end of the list, which helps to preserve the label's integrity. Less cumbersome, rdf:Seq preserves the order of items, but without clear identification of the end of the list.

2.3 madsrdf:RWO

A madsrdf:RWO is an abstract entity and identifies a Real World Object (RWO).  A madsrdf:RWO resource records information that more appropriately describes aspects of the RWO rather than the conceptual resource, the madsrdf:Authority.  A madsrdf:Authority relates to madsrdf:RWO with the madsrdf:identifiesRWO object property.  The properties - madsrdf:fieldOfActivity, madsrdf:hasAffiliation, and madsrdf:Affiliation - relate directly or indirectly to a madsrdf:RWO, not a madsrdf:Authority.  

Example: RWO

<rdf:RDF xmlns:madsrdf=""
<madsrdf:PersonalName rdf:about="ex:Laborman_Jay">
   <rdf:type rdf:resource=""/>
   <madsrdf:authoritativeLabel xml:lang="en">Laborman, Jay</madsrdf:authoritativeLabel>
         <rdf:type rdf:resource=""/>
               <madsrdf:affiliatedWith>World Resources Institute, Washington, D.C.</madsrdf:affiliatedWith>
               <madsrdf:affiliatedWith>Georgetown University, Law Center, Washington, D.C.</madsrdf:affiliatedWith>
               <madsrdf:affiliatedWith>New York University, New York, N.Y.</madsrdf:affiliatedWith>
         <madsrdf:fieldOfActivity>Director of environmental organization</madsrdf:fieldOfActivity>
         <madsrdf:fieldOfActivity>college teacher</madsrdf:fieldOfActivity>
@prefix xml: <>.
@prefix xmlns: <>.
@prefix madsrdf: <>.
@prefix rdf: <>.
<ex:Laborman_Jay> madsrdf:authoritativeLabel "Laborman, Jay"@en;
	madsrdf:identifiesRWO _:bnode1273305600;
	a madsrdf:Authority,
_:bnode1273305600 madsrdf:fieldOfActivity "college teacher",
		"Director of environmental organization";
	madsrdf:hasAffiliation _:bnode381072256,
	a madsrdf:RWO,
_:bnode1839014784 madsrdf:affiliatedWith "Georgetown University, Law Center, Washington, D.C.";
	madsrdf:affiliationBegan "2007";
	a madsrdf:Affiliation.
_:bnode235865472 madsrdf:affiliatedWith "World Resources Institute, Washington, D.C.";
	madsrdf:affiliationBegan "2007";
	a madsrdf:Affiliation.
_:bnode381072256 madsrdf:affiliatedWith "New York University, New York, N.Y.";
	madsrdf:affiliationBegan "2002";
	a madsrdf:Affiliation.
<ex:Laborman_Jay> <> <>.
<ex:Laborman_Jay> <> <>.
<ex:Laborman_Jay> <> "Laborman, Jay"@en.
_:bnode1273305600 <> <>.
_:bnode1273305600 <> <>.
_:bnode235865472 <> <>.
_:bnode235865472 <> "World Resources Institute, Washington, D.C.".
_:bnode235865472 <> "2007".
_:bnode1273305600 <> _:bnode235865472.
_:bnode1839014784 <> <>.
_:bnode1839014784 <> "Georgetown University, Law Center, Washington, D.C.".
_:bnode1839014784 <> "2007".
_:bnode1273305600 <> _:bnode1839014784.
_:bnode381072256 <> <>.
_:bnode381072256 <> "New York University, New York, N.Y.".
_:bnode381072256 <> "2002".
_:bnode1273305600 <> _:bnode381072256.
_:bnode1273305600 <> "Director of environmental organization".
_:bnode1273305600 <> "college teacher".
<ex:Laborman_Jay> <> _:bnode1273305600.

It is expected that well-known Classes from other vocabularies, such as foaf:Agent, might sub-class madsrdf:RWO (or vice-versa).   The madsrdf:RWO class is disjoint with madsrdf:Authority, madsrdf:DeprecatedAuthority, and madsrdf:Variant.

2.4 madsrdf:MADSScheme and madsrdf:MADSCollection

A madsrdf:MADSScheme is an organizational unit.  It describes a knowledge organization system and aggregates the madsrdf:Authority descriptions and/or madsrdf:MADSCollection resources included in the knowledge organization system.  A madsrdf:MADSScheme can include madsrdf:Authority descriptions and madsrdf:MADSCollection resources with the madsrdf:hasMADSSchemeMember property (there is an inverse property: madsrdf:isMemberOfMADSScheme).

A madsrdf:MADSCollection is also an organizational unit.  Members of a madsrdf:MADSCollection will have some form of intellectually unifying theme – such as grouping LCSH madsrdf:Authority descriptions that may be used as temporal subdivisions - but not to the extent that it defines an independent knowledge organization system.  madsrdf:MADSCollection resources aggregate madsrdf:Authority descriptions or other madsrdf:MADSCollection resources.  madsrdf:MADSCollection resources maybe used to group madsrdf:Authority descriptions in order to further distinguish the madsrdf:Authority descriptions within the madsrdf:MADSScheme.  For instance, to use LCSH as an example, if a madsrdf:Authority description can be used as a temporal subdivision, then that madsrdf:Authority might also belong to a madsrdf:MADSCollection that aggregates resources to be employed as temporal subdivisions.  

madsrdf:Authority descriptions are associated with a madsrdf:MADSCollection via the madsrdf:hasMADSCollectionMember object property.  Establishing a relationship is optional and should be considered with care – when a madsrdf:MADSCollection is part of a madsrdf:MADSScheme, then any madsrdf:Authority within that madsrdf:MADSCollection is effectively also in the madsrdf:MADSScheme.  Returning briefly to the example above, the collection of temporal subdivisions could be part of the madsrdf:MADSScheme.  However, a madsrdf:MADSCollection does not need to be associated with a madsrdf:MADSScheme.  

Example: MADSScheme and MADSCollection

<rdf:RDF xmlns:rdf=""

  <rdf:Description rdf:about="ex:LCSH">
    <rdf:type rdf:resource=""/>
    <madsrdf:hasMADSSchemeMember rdf:resource="ex:18thCentury"/>
    <madsrdf:hasMADSSchemeMember rdf:resource="ex:Collection_TemporalSubdivisions"/>
  <rdf:Description rdf:about="ex:18thCentury">
    <rdf:type rdf:resource=""/>
    <madsrdf:isMemberOfMADSScheme rdf:resource="ex:LCSH"/>
    <madsrdf:isMemberOfMADSCollection rdf:resource="ex:Collection_TemporalSubdivisions"/>
  <rdf:Description rdf:about="ex:Collection_TemporalSubdivisions">
    <rdf:type rdf:resource=""/>
    <madsrdf:isMemberOfMADSScheme rdf:resource="ex:LCSH"/>
    <madsrdf:hasMADSCollectionMember rdf:resource="ex:18thCentury"/>

@prefix madsrdf: <>.
@prefix rdf: <>.
<ex:18thCentury> madsrdf:isMemberOfMADSCollection <ex:Collection_TemporalSubdivisions>;
  madsrdf:isMemberOfMADSScheme <ex:LCSH>;
  a madsrdf:Authority.
<ex:Collection_TemporalSubdivisions> madsrdf:hasMADSCollectionMember <ex:18thCentury>;
  madsrdf:isMemberOfMADSScheme <ex:LCSH>;
  a madsrdf:MADSCollection.
<ex:LCSH> madsrdf:hasMADSSchemeMember <ex:18thCentury>,
  a madsrdf:MADSScheme.

<ex:LCSH> <> <>.
<ex:LCSH> <> <ex:18thCentury>.
<ex:LCSH> <> <ex:Collection_TemporalSubdivisions>.
<ex:18thCentury> <> <>.
<ex:18thCentury> <> <ex:LCSH>.
<ex:18thCentury> <> <ex:Collection_TemporalSubdivisions>.
<ex:Collection_TemporalSubdivisions> <> <>.
<ex:Collection_TemporalSubdivisions> <> <ex:LCSH>.
<ex:Collection_TemporalSubdivisions> <> <ex:18thCentury>.

Such a model does not embed scheme-specific rules within MADS/RDF but still allows for the organization of the scheme and its aspects in a structured manner.

2.5 madsrdf:Element

The madsrdf:Element class, and its associated sub-classes, provide a way to describe the parts of labels.  For example, the name “Black Foot, Chief, d. 1877” can be broken into 3 parts, or elements.  “Black Foot” is the madsrdf:NameElement; “Chief” is the madsrdf:TermsOfAddressNameElement; and “d. 1877” is the madsrdf:DateNameElement.  The madsrdf:elementList property, which, like madsrdf:componentList, is used to organize the various parts of labels.  It has a range of rdf:List.

Example: Label Elements

  <madsrdf:PersonalName rdf:about="ex:Black_Foot,_Chief,_d._1877">
    <rdf:type rdf:resource=""/>
    <madsrdf:authoritativeLabel>Black Foot, Chief, d. 1877</madsrdf:authoritativeLabel>
    <madsrdf:elementList rdf:parseType="Collection">
        <madsrdf:elementValue>Black Foot,</madsrdf:elementValue>
        <madsrdf:elementValue>d. 1877</madsrdf:elementValue>
@prefix madsrdf: <>.
@prefix rdf: <>.
<ex:Black_Foot,_Chief,_d._1877> madsrdf:authoritativeLabel "Black Foot, Chief, d. 1877";
  madsrdf:elementList (_:bnode177631232 _:bnode1668942528 _:bnode1962097920);
  a madsrdf:Authority,
_:bnode1668942528 madsrdf:elementValue "Chief,";
  a madsrdf:TermsOfAddressElement.
_:bnode177631232 madsrdf:elementValue "Black Foot,";
  a madsrdf:NameElement.
_:bnode1962097920 madsrdf:elementValue "d. 1877";
  a madsrdf:DateNameElement.
<ex:Black_Foot,_Chief,_d._1877> <> <>.
<ex:Black_Foot,_Chief,_d._1877> <> <>.
<ex:Black_Foot,_Chief,_d._1877> <> "Black Foot, Chief, d. 1877".
_:bnode177631232 <> <>.
_:bnode177631232 <> "Black Foot,".
_:bnode859808896 <> _:bnode177631232.
_:bnode859808896 <> _:bnode1588584640.
_:bnode1668942528 <> <>.
_:bnode1668942528 <> "Chief,".
_:bnode1588584640 <> _:bnode1668942528.
_:bnode1588584640 <> _:bnode405937728.
_:bnode1962097920 <> <>.
_:bnode1962097920 <> "d. 1877".
_:bnode405937728 <> _:bnode1962097920.
_:bnode405937728 <> <>.
<ex:Black_Foot,_Chief,_d._1877> <> _:bnode859808896.

madsrdf:elementList does not, currently, have a domain, thereby permitting it to be used with madsrdf:ComplexType descriptions.  It is, however, generally associated with a madsrdf:SimpleType.

3 MADS/RDF Object Properties

Not all Object Properties are discussed in this section.  Some have been treated earlier in this document, especially those pertaining to madsrdf:MADSScheme types and madsrdf:MADSCollection types.

All the Object Properties meant to indicate a (potential) high-value relationship are prefixed with the English verb “has.”  Employing camel-case, the second part identifies the type of relationship and the third, if used, identifies the target of the relationship.  

3.1 madsrdf:hasVariant

madsrdf:hasVariant, with a domain of madsrdf:Authority and a range of madsrdf:Variant, relates a madsrdf:Authority to a madsrdf:Variant.  madsrdf:hasVariant has no inverse property relationship.  In most circumstances, a blank node will be used though it may instead be identified with a URI.  madsrdf:hasVariant is a sub-property of skosxl:altLabel; it represents a lexical entity versus an independent concept.

3.2 madsrdf:identifiesRWO and madsrdf:isIdentifiedByAuthority

madsrdf:identifiesRWO is a sub-property of foaf:focus.  It relates a resource representing a concept of something to the thing itself, a RWO.   It has a domain of madsrdf:Authority and a range of madsrdf:RWO.  madsrdf:isIdentifiedByAuthority is its inverse, and provides a way to relate a thing to its conceptualization.  It has no mapping to an external property.

3.3 Relationships -  madsrdf:hasRelatedAuthority

madsrdf:hasRelatedAuthority can be equated with skos:semanticRelation and, as such, is designed as an umbrella property for all of its sub-properties.  The property, however, states, at best, a vague ill-defined relationship, simply that one Authority has some form of relationship with another Authority.  madsrdf:hasRelatedAuthority has a domain of madsrdf:Authority and a range of madsrdf:Authority.  The sub-properties – most of which were defined in MADS/XML – more precisely illustrate the relationship between two madsrdf:Authority descriptions.    Relationships in MADS/RDF map, for the most part, with their SKOS equivalents.  And, although different semantics were adopted, the related SKOS property should be readily obvious.

3.3.1 madsrdf:hasBroaderAuthority and madsrdf:hasNarrowerAuthority

These are designed to associate a madsrdf:Authority with a more broader (general) or narrower (specific) concept.  These have an inverse relationship with each other.  MADS/XML supports these relationships.

3.3.2 madsrdf:hasBroaderExternalAuthority and madsrdf:hasNarrowerExternalAuthorityThese relationships have been added to accommodate the SKOS equivalents (skos:broadMatch and skos:narrowMatch).  They assist with linking madsrdf:Authority descriptions in one madsrdf:MADSScheme to a term found in a different madsrdf:MADSScheme.    These are sub-properties of their respective non-external relationship type.  They are not represented in MADS/XML.

3.3.3 madsrdf:hasReciprocalAuthority and madsrdf:hasReciprocalExternalAuthority

madsrdf:hasReciprocalAuthority relates to madsrdf:Authority descriptions with each other so long as the relationship is shared, reciprocally.  MADS/XML supports this relationship with the “equivalent” relationship type value.  madsrdf:hasReciprocalExternalAuthority – a sub-property of madsrdf:hasReciprocalAuthority - does the same for madsrdf:Authority records in other madsrdf:MADSSchemes.

3.3.4 madsrdf:hasCloseExternalAuthority and madsrdf:hasExactExternalAuthority

These have been added to accommodate the SKOS equivalents (skos:closeMatch, skos:exactMatch).  They relate madsrdf:Authority descriptions in two different madsrdf:MADSSchemes.

3.3.5 madsrdf:hasCorporateParentAuthority and madsrdf:hasCorporateSubsidiaryAuthority

These properties are in MADS/XML – known as parentOrg - and serve to relate the descriptions for corporate entities.  They are inversely related to each other.

3.4 Relationships between Current, Deprecated, and Superseded Descriptions

The following object properties are sub-properties of madsrdf:see.  madsrdf:see simply denotes a relationship between a madsrdf:Authority and/or a madsrdf:DeprecatedAuthority.  There is no certainty that the related resource will illuminate the original resource.

3.4.1 madsrdf:hasLaterEstablishedForm and madsrdf:hasEarlierEstablishedForm

madsrdf:hasLaterEstablishedForm relates a resource to a madsrdf:Authority description developed afterwards.  madsrdf:hasLaterEstablishedForm may relate two authoritative descriptions, one of which followed the other but both of which are still valid, or it may relate a madsrdf:DeprecatedAuthority to its now authoritative representation.

For example, in the case of the former – madsrdf:hasLaterEstablishedForm relates two still-valid madsrdf:Authority resources - the “Minnesota Mining and Manufacturing Company,” from the LC Name Authority File, has a later established form, “3M Company,” but “Minnesota Mining and Manufacturing Company” remains authoritative when used to describe something that pertains specifically to the time when the “3M Company” was known as the “Minnesota Mining and Manufacturing Company.”

MADS/XML supports the relationship madsrdf:hasLaterEstablishedForm.  SKOS has no equivalent.

madsrdf:hasEarlierEstablishedForm is the inverse of madsrdf:hasLaterEstablishedForm.  MADS/XML provides support for this relationship.

3.4.2 madsrdf:useInstead and madsrdf:useFor

These object properties relate madsrdf:Authority and/or madsrdf:DeprecatedAuthority descriptions to each other.  There is no certainty that the related description will further illuminate the original description.  For example, madsrdf:useInstead, meaning “Use [This Other Resource] Instead,” can relate a madsrdf:DeprecatedAuthority to a madsrdf:Authority, especially to direct agents from a madsrdf:DeprecatedAuthority to its replacement.  madsrdf:useFor is the inverse of madsrdf:useInstead.

4 Acknowledgements

The MADS/RDF to SKOS/RDF mapping was done by Antoine Isaac.  The MADS/RDF model and ontology benefited significantly as a result of the fruitful discussions surrounding his effort to map the MADS/RDF ontology to SKOS.