Dear All:
Under “About the logical expressions used in the CIDOC CRM”, we find
these paragraphs:
The present CIDOC CRM specifications are annotated with logical axioms,
providing an additional formal expression of the CIDOC CRM ontology.
This section briefly introduces the assumptions that are at the basis of
the logical expression of the CIDOC CRM (for a fully detailed account of
the logical expression of semantic data modelling, see (Reiter,1984)).
The CIDOC CRM is expressed in terms of the primitives of semantic data
modelling. As such, it consists of:
· classes,which represent general notions in the domain of discourse,
such as the CIDOC CRM class E21 Person which represents the notion of
person;
· properties,which represent the binary relations that link the
individuals in the domain of discourse, such as the CIDOC CRM property
P152 has parent linking a person to one of the person’s parent.
Classes and properties are used to express ontological knowledge by
means of various kinds of constraints, such as sub-class/sub-property
links, e.g., E21 Personis a sub-class ofE20 Biological Object, or
domain/range constraints, e.g., the domain of P152 has parentis class
E21 Person.
In contrast, first-order logic-based knowledge representation relies on
a language for formally encoding an ontology. This language can be
directly put in correspondence with semantic data modelling in a
straightforward way:
· classes are named by unary predicate symbols; conventionally, we
use E21 as the unary predicate symbol corresponding to class E21 Person;
· properties are named by binary predicate symbols; conventionally,
we use P152 as the binary predicate symbol corresponding to property
P152 has parent.
· properties of properties, “.1 properties” are named by ternary
predicate symbols; conventionally, we use P14.1 as the ternary predicate
symbol corresponding to property P14.1 in the role of.
—---------------------------------------------------------
Under “About Types”, we find this paragraph:
Analogous to the function of the P2 has type (is type of)property, some
properties in the CIDOC CRM are associated with an additional property.
These are numbered in the CIDOC CRM documentation with a ‘.1’ extension.
The range of these properties of properties always falls under E55 Type.
The purpose of a property of a property is to provide an alternative
mechanism to specialize its domain property through the use of property
subtypes declared as instances of E55 Type. They do not appear in the
property hierarchy list but are included as part of the property
declarations and referred to in the class declarations. For example,
P62.1 mode of depiction: E55 Type is associated with E24 Physical
Man-made Thing. P62 depicts (is depicted by): E1 CRM Entity.
---------------------------------------------------------------------------------------------------------------------
However, we completely missa statement about the actual form of the CRM
under “Applied Form” in thefirst place!.
Instead, it is implicit in “About the logical expressions used in the
CIDOC CRM”, as shown above, and *misses properties of properties.*
I therefore propose (changes in yellow):
Applied Form
The CIDOC CRM is an ontology in the sense used in computer science. It
has been expressed as an object-oriented semantic model, in the hope
that this formulation will be comprehensible to both documentation
experts and information scientists alike, while at the same time being
readily converted to machine-readable formats such as RDF Schema or OWL.
A CRM conformant documentation system can be implemented using RDF
Schema or OWL, but also in Relational or Object-Oriented schema. CIDOC
CRM instances can be encoded in RDF, JSON LD, XML, OWL and others.
More specifically, the CIDOC CRM is expressed in terms of the primitives
of semantic data modelling. As such, it consists of:
· classes,which represent general notions in the domain of discourse,
such as the CIDOC CRM class E21 Person which represents the notion of
person;
· properties,which represent the binary relations that link the
individuals in the domain of discourse, such as the CIDOC CRM property
P152 has parent linking a person to one of the person’s parent.
*
properties of properties, such as the property P14.1 in the role of
of the CIDOC CRMproperty P14 carried out by (see also section
“About Types”). (They do not appear in the property hierarchy list,
but are included as part of their base property declaration and are
referred to in the class declarations. They all have the implicit
quantification “many to many” (see also section “Property Quantifiers”))
Although the definition of the CIDOC CRM provided here is complete, it
is an intentionally compact and concise presentation of the CIDOC CRM’s
81 classes and 160 unique properties. It does not attempt to articulate
the inheritance of properties by subclasses throughout the class
hierarchy (this would require the declaration of several thousand
properties, as opposed to 160). However, this definition does contain
all of the information necessary to infer and automatically generate a
full declaration of all properties, including inherited properties.
—-------------------------------------------------------------------------------------
Add to Naming Conventions:a *last bullet item*:
· Properties of properties are identified by “P”, followed by the
number of the base property extended with “.1” and are named in one
direction using a verbal phrase in lower case in the present tense. For
example: the property P62.1 mode of depiction of the property P62
depicts (is depicted by).
—--------------------------------------------------------------------------------------
About the logical expressions used in the CIDOC CRM”
The present CIDOC CRM specifications are annotated with logical axioms,
providing an additional formal expression of the CIDOC CRM ontology.
This section briefly introduces the assumptions that are at the basis of
the logical expression of the CIDOC CRM (for a fully detailed account of
the logical expression of semantic data modelling, see (Reiter,1984)).
(delete the text copied into "Applied Form").
In terms of semantic data modelling, classes and properties are used to
express ontological knowledge by means of various kinds of constraints,
such as sub-class/sub-property links, e.g., E21 Personis a sub-class
ofE20 Biological Object, or domain/range constraints, e.g., the domain
of P152 has parentis class E21 Person.
In contrast, first-order logic-based knowledge representation relies on
a language for formally encoding an ontology. This language can be
directly put in correspondence with semantic data modelling in a
straightforward way:
· classes are named by unary predicate symbols; conventionally, we
use E21 as the unary predicate symbol corresponding to class E21 Person;
· properties are named by binary predicate symbols; conventionally,
we use P152 as the binary predicate symbol corresponding to property
P152 has parent.
· properties of properties, “.1 properties”, are named by ternary
predicate symbols; conventionally, we use P14.1 as the ternary predicate
symbol corresponding to property P14.1 in the role of.
………
—----------------------------------------------------------------------------------------------------------------
Add at the end of “Property Quantifiers” :
Note that the quantification of all properties of properties, “.1
properties”, is “many to many”, and therefore does not appear explicitly
in their definitions.
—--------------------------------------------------------------------------------------------------------------------------
--
------------------------------------
Dr. Martin Doerr
Honorary Head of the
Center for Cultural Informatics
Information Systems Laboratory
Institute of Computer Science
Foundation for Research and Technology - Hellas (FORTH)
N.Plastira 100, Vassilika Vouton,
GR70013 Heraklion,Crete,Greece
Vox:+30(2810)391625
Email:mar...@ics.forth.gr
Web-site:http://www.ics.forth.gr/isl
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