Pat, Matthew (01)
Considered from a legal point of view, a person and a role such
as employee should surely be treated through a role-relationship, rather
than a subtype relationship, since one's capacity to act depends on
one's status. I have no right to marry in virtue of being an employee,
but I can marry as a person. Conversely, I can authorize a design in my
role as a project manager (a subtype of employee), but not I cannot do
it in virtue of being a person, since the company process applies to
employees of the company, not to persons in general. I may also have
rights both as a person and an employee (e.g. my manager may not shoot
me, both as an obligation under common law, and because of the
anti-bullying policy).
The distinction is not one of time, and I do not slice between
one and another, although then role-relation may be qualified, e.g. by
my start date and required retirement date. (02)
Sean Barker
BAE SYSTEMS - Advanced Technology Centre
Bristol, UK
+44(0) 117 302 8184 (03)
BAE Systems (Operations) Limited
Registered Office: Warwick House, PO Box 87, Farnborough Aerospace
Centre, Farnborough, Hants, GU14 6YU, UK
Registered in England & Wales No: 1996687 (04)
> -----Original Message-----
> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
> [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of
> Patrick Cassidy
> Sent: 19 March 2008 09:36
> To: '[ontolog-forum] '
> Subject: Re: [ontolog-forum] Ontology similarity and accurate
> communication
>
>
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>
> Matthew,
> If one were to attempt to create instances of a 3D Person
> that were also instances of a role, the multiplicity you
> refer to would be a problem. In the illustration below,
> Matthew is an instance of 3D Person, not an instance of
> Employee - if Matthew were an instance of Employee, the
> problem you describe would then present itself. But we can
> create instances of Role such as an Employee that have a
> Person as a filler. Nevertheless the *Role* "Employee" is
> also a subtype of Person, therefore an instance of an
> Employee is always an instance of a Person, implicitly though
> not explicitly. But the instances of a Role such as Employee
> are more like time slices and are not identical to the
> instance of Person that fills the role. The multiplicity is
> in the multiplicity of TimeSlices, as there are in a 4D
> representation; every different TimeSlice is a different
> entity. The way that can work is illustrated below using OWL.
> One comment I made was not phrased properly:
> [PC] > > (3) a person can be an instance of multiple roles
> in any given
> time
> > > interval
> It would more accurately have been phrased that:
> (3a) an instance of Person can fill multiple roles in any
> given time frame
> (3b) a timeslice of Person can be an instance of multiple roles
> (3c) an instance of Role in any given time interval can be
> an instance of Person - because Person and Role are not disjoint.
> The illustration below should clarify what that means.
>
> Perhaps the non-intuitive element is that an instance of a Role (a
> TimeSLice) can also be an instance of a Person(a
> dimension-neutral Type) - because the type Person is not
> disjoint with the type TimeSlice. In the illustration below,
> Matthew is a Person, but the instance
> MatthewAsEmployeeOfShellAndLeeds is a Role - and also an
> instance of Person
> - but is not identical to Matthew. It is more like a
> TimeSlice of Matthew.
> Even So, Matthew is not necessarily 3D or 4D, Matthew is a
> dimension-neutral entity.
> If one were to use a formalism that permitted relation
> arities higher than two, it would be possible to specify
> roles and their time limits without using time slices.
> TimeSlices (among which are Roles) are syntactically
> convenient when using OWL, they aren't logically necessary.
> They have the same logical effect as an explicit time-indexed
> assertion on a dimension-neutral entity. In that case, there
> would be no TimeSlices, only time-indexed assertions (which
> are logically equivalent, after translation, to assertions on
> TimeSlices). The axioms to translate the two formalisms are
> not here because this is a pure OWL representation.
>
> All instance of Role should have start and end times
> specified - they are time slices.
> Person is in this case neither exclusively 3D nor 4D - time
> slices can be generated by making a person an instance of
> 'TimeSlice', or an instance of Role, which is a subtype of
> TimeSlice. Every TimeSlice has a start time and end time.
> But an instance of Person can also have attributes and
> relations specified by explicit time-indexed relations,
> without using TimeSlices.
>
> In the following note that an Employee is a Role, and
> something can be an instance of an Object as well as a Role.
> (definitions - some parts are from Cyc - are abbreviated).
>
> HumanRole is a subtype of Person and Role
> Every HumanRole is a Role whose RoleFiller is a Person
> (restriction)
> PersonWithOccupation is a subtype of HumanRole
>
> <owl:Class rdf:ID="Employee">
> <rdfs:comment>A Person who was employed by another
> Agent in some hiring event.</rdfs:comment>
> <rdf:type rdf:resource="#PersonType"/>
> <rdf:type rdf:resource="#RoleType"/>
> <rdfs:subClassOf rdf:resource="#TemporaryRoleCreatedByEvent"/>
> <rdfs:subClassOf rdf:resource="#PersonWithOccupation"/>
> <rdfs:subClassOf>
> <owl:Restriction>
> <owl:onProperty>
> <owl:ObjectProperty rdf:about="#isEmployedBy"/>
> </owl:onProperty>
> <owl:someValuesFrom rdf:resource="#IntelligentAgent"/>
> </owl:Restriction>
> </rdfs:subClassOf>
> </owl:Class>
>
> **** NOTE that 'employee' is a subtype of 'Person' ****
>
> <owl:Class rdf:ID="EmployeeOfShell">
> <rdfs:subClassOf rdf:resource="#Employee "/>
> <rdfs:comment>A person who is an employee of Shell.</rdfs:comment>
> </owl:Class>
>
> <owl:Class rdf:ID="EmployeeOfLeeds">
> <rdfs:subClassOf rdf:resource="#Employee "/>
> <rdfs:comment>A person who is an employee of Leeds.</rdfs:comment>
> </owl:Class>
>
> <!-- Matthew is employee of Shell from 1990 to 2008
> Matthew is employee of Leeds from 1980 to 2004
> -->
>
> <Person rdf:ID="Matthew"/>
>
> <EmployeeOfShell rdf:ID="MatthewAsEmployeeOfLeedsAndShell">
> <rdf:type rdf:resource="#EmployeeOfLeeds"/>
> <hasRoleFiller rdf:resource="#Matthew"/>
> <rdfs:comment>Matthew is an Employee of Both Shell
> and Leeds from the beginning of
> 1990 to the end of 2004.</rdfs:comment>
> <hasStartingTimePoint rdf:ID="DTEG19900101T0000"/>
> <hasEndingTimePoint rdf:ID="DTEG20041212T2400"/>
> </EmployeeOfShell >
>
> Pat
>
> Patrick Cassidy
> MICRA, Inc.
> 908-561-3416
> cell: 908-565-4053
> cassidy@xxxxxxxxx
>
>
> > -----Original Message-----
> > From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-
> > bounces@xxxxxxxxxxxxxxxx] On Behalf Of matthew.west@xxxxxxxxx
> > Sent: Tuesday, March 18, 2008 2:42 PM
> > To: ontolog-forum@xxxxxxxxxxxxxxxx
> > Subject: Re: [ontolog-forum] Ontology similarity and accurate
> > communication
> >
> > Dear Pat,
> >
> > > This is a good issue, but I think it has a resolution
> without the
> > > problem you envision, because in 3D the types of an entity can
> > > change with time.
> > >
> > > (1) employee is a role, which means that it must be
> time indexed.
> > > (2) every instance of employee (in some time interval) is an
> > > instance of person (in that time interval)
> > > (3) a person can be an instance of multiple roles in any given
> > > time interval
> > > (4) in some time interval Matthew can be an instance of
> "Employee
> > of
> > > Shell" and "Employee of Leeds U"
> >
> > MW: What you are missing is that EACH instance of employee
> MUST be a
> > separate person if employee is a subtype of person. To put that the
> > other way round, if I am just one person and there is an employee
> > subtype of person, then I either am or am not an instance
> of employee,
> > but I can only be an instance of employee once.
> >
> > MW: If you think that a Person can be more than one
> employee, then the
> > relationship between person and employee is something other than
> > subtype/supertype.
> >
> > MW: If I were a 3D-ist then I would suggest somthing like a
> consists
> > of relation.
> >
> > >
> > > In 4D, I believe that the 4D worms will intersect, and that is
> > > another way of viewing the same thing, but it is only
> inconsistent
> > > if one assigns the same type "Person" to a 4d object in
> one ontology
> > > and a 3D object in the other, and then tries to use the
> same term to
> > > represent the two different types.
> >
> > MW: In 4D it is quite clear, and employee is a state of a
> person, and
> > the relationship between person and employee is temporal part of.
> > Both employee and person are subtypes of state_of_person.
> >
> > MW: The interesting thing about temporal part of is that most
> > properties are inherited by substates (except for example being a
> > person for the whole of their life).
> >
> >
> > Regards
> >
> > Matthew West
> > Reference Data Architecture and Standards Manager Shell
> International
> > Petroleum Company Limited Registered in England and Wales
> Registered
> > number: 621148 Registered office: Shell Centre, London SE1
> 7NA, United
> > Kingdom
> >
> > Tel: +44 20 7934 4490 Mobile: +44 7796 336538
> > Email: matthew.west@xxxxxxxxx
> > http://www.shell.com
> > http://www.matthew-west.org.uk/
> >
> > >
> > > I need to be more specific. Another day or two for my more
> > > detailed reply to PatH.
> > >
> > > Pat
> > >
> > > Patrick Cassidy
> > > MICRA, Inc.
> > > 908-561-3416
> > > cell: 908-565-4053
> > > cassidy@xxxxxxxxx
> > >
> > >
> > > > -----Original Message-----
> > > > From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
> > > > [mailto:ontolog-forum- bounces@xxxxxxxxxxxxxxxx] On Behalf Of
> > > > matthew.west@xxxxxxxxx
> > > > Sent: Tuesday, March 18, 2008 5:18 AM
> > > > To: ontolog-forum@xxxxxxxxxxxxxxxx
> > > > Subject: Re: [ontolog-forum] Ontology similarity and accurate
> > > > communication
> > > >
> > > > Dear John,
> > > >
> > > > > MW> So for example, there are ontologies where you will
> > > find employee
> > > > > > as a subtype of person, and others that understand
> it is not.
> > > > >
> > > > > I don't know which way you are advocating, but I'll
> summarize my
> > > > > position:
> > > > >
> > > > > 1. There is a fundamental distinction between natural
> > > types, such
> > > > > as Cat or HumanBeing, and role types, such as Pet or
> > > Employee.
> > > > >
> > > > > 2. Every instance of a role type is a subytpe of some
> > > natural type,
> > > > > but it may also be a subtype of other role types.
> > > > > HeartSpecialist
> > > > > is a subtype of Physician, which is a subtype of
> HumanBeing.
> > > > >
> > > > MW: I do mean that employee is not a subtype of person
> (or human
> > > > being).
> > > >
> > > > MW: If we remind ourselves of what being a subtype means,
> > > it means that
> > > > each instance of a subtype is an instance of the supertype.
> > > Now ler us
> > > > look at an example. I am an employee of both Shell and Leeds
> > > > University.
> > > > I have different employee numbers, very different salaries, and
> > > > different start dates. Now if employee is a subtype of
> person then
> > > > each of these is a person, i.e. there are two of me.
> > > >
> > > > MW: This kind of situation is true of roles generally, you can
> > > > play multiple roles at the same time and the same role multiple
> > > > times (and at the same time). These do not all generate
> new people.
> > > >
> > > > MW: So the question is: what is the relationship between a role
> > > > and the person who plays is. Fortunately, as a
> > > 4-dimensionalist, there
> > > > is a simple answer. The role is a temporal part of the
> person that
> > > > plays the role, or if you prefer, the person for a period of
> > > > time, rather than for the whole of their life.
> > > >
> > > > MW: This is not so different from the question of the
> vase and the
> > > > piece of clay. Are pots subtypes of clay? Or is the pot a
> > > > different object than the piece of clay it is made from?
> > > >
> > > > Regards
> > > >
> > > > Matthew West
> > > > Reference Data Architecture and Standards Manager Shell
> > > > International Petroleum Company Limited Registered in
> England and
> > > > Wales Registered number: 621148 Registered office:
> Shell Centre,
> > > > London SE1 7NA, United Kingdom
> > > >
> > > > Tel: +44 20 7934 4490 Mobile: +44 7796 336538
> > > > Email: matthew.west@xxxxxxxxx
> > > > http://www.shell.com
> > > > http://www.matthew-west.org.uk/
> > > >
> > > >
> > > >
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