[Person-ontology] first contributions - is the Higgins top-level useful?
Pat Hayes
phayes at ihmc.us
Thu Oct 11 08:33:50 PDT 2007
>Let me try to put this into actual RDF/XML based on higgins.owl
>
><higgins:DigitalSubject rdf:about="urn:adam">
> <hasHairColor rdf:resource="urn:value1">
></higgins:DigitalSubject>
><higgins:String rdf:about="urn:value1">
> <higgins:string>blond</higgins:string>
> <higgins:source>DMV</higgins:source> <!--
>This is a simplification, "source" should
>actually have a SubjectRelation as value -->
> <higgins:expires>Jan 1, 2010</higgins:expires>
></higgins:String>
>
>So while it is true that strictly speaking the
>metadata (expires, source) is applied to value1
>instead of the whole statement, it really
>doesn't matter, since value1 is only used as the
>value of a single statement.
Two points. First, this is a very fragile and
error-prone way to build an ontology, since you
are relying heavily on what in RDF is a syntactic
accident with no semantic meaning. This will work
for a while if you are very careful, but it will
almost certainly break when you start trying to
do nontrivial inferencing (in RDFS, certainly in
OWL). No conforming tools will be able to tell
you the source of the bugs that arise, since they
will not know your idiosyncratic conventions.
Second, it does matter, since the 'value' is
asserted to be the object of the property
hasHairColor. Tell me now, please, what the range
of hasHairColor is? It is apparently not hair
colors; it is strange entities which have
associated dates and information sources, which
apply to the assertion in which the value occurs.
But how far 'out' do these dates and other
properties extend? Suppose what I have - say, a
property restriction - so which when mapped back
into OWL/RDF becomes a small RDF subgraph rather
than a single triple. How do I know to which
triples in a larger graph the dates attached to a
value are meant to apply?
With the greatest respect, the only way I would
describe the Higgins ontology is
<string>broken</string>. It is trying to graft an
alien conceptual framework into RDF in a way that
does not naturally fit. The fact that the entire
XML Schema datatype system had to be reified
should have been a red flag that something wasn't
going correctly.
Pat Hayes
>In fact we could also do the same thing with a blank node:
>
><higgins:DigitalSubject rdf:about="urn:adam">
> <hasHairColor rdf:parseType="Resource">
> <rdf:type rdf:resource="&higgins;String">
> <higgins:string>blond</higgins:string>
> <higgins:source>DMV</higgins:source>
> <higgins:expires>Jan 1, 2010</higgins:expires>
> </hasHairColor>
></higgins:DigitalSubject>
>
>Markus
>
>On 10/10/07, David Whitten
><<mailto:david.j.whitten at gmail.com>david.j.whitten at gmail.com>
>wrote:
>
>Oh,
>I expected that is exactly what you meant.
>Unfortunately, that is not what the logical statements were.
>You mentioned on another thread about
>difficulties with with reifying statements.
>
>You actually want the "expires jan 1, 2010" to
>apply to the reified statement that "Adam has
>HairColor blonde"
>rather than to the value of "Adam hasHairColor"
>
>As stated, you said the expires predicate
>applied to value1 and value of value1 is
>"blonde"
>
>(as an aside, isn't blonde the colour of women's
>hair and blond the color of men's hair? I seem
>to recall some English teacher drilling that
>into my head at some point...)
>
>I expected what you meant to say was:
>
> value1 value (Adam hasHairColor "blonde")
> value1 expires "Jan 1, 2010"
> value1 source "Dept of Motor Vehicles"
>
>
>I used a parenthesis to indicate the predicate
>as a whole you should tell us what the syntax
>that you have in Higgins that you use to tie a value to a reified statement.
>
>Best Regards,
>David
>
>
>On 10/9/07, Paul Trevithick
><<mailto:paul at socialphysics.org>
>paul at socialphysics.org> wrote:
>
>What I meant by the two statements "value1
>expires Jan 1, 2010" and "value1 source DMV"
>taken together is that the fact that Adam has
>blonde hair as attested by the DMV is a
>statement that is considered authoritative on or
>before Jan 1, 2010. "DMV" is the source of the
>value, "Jan 1, 2010" is the date after which
>they are no longer willing to stand behind that
>assertion.
>
>
>
>
>From: David Whitten
>[mailto:<mailto:david.j.whitten at gmail.com>david.j.whitten at gmail.com]
>Sent: Tuesday, October 09, 2007 8:27 PM
>To: Paul Trevithick
>Cc:
><mailto:phmartin at phmartin.info>phmartin at phmartin.info;
><mailto:person-ontology at idcommons.net>person-ontology at idcommons.net
>Subject: Re: [Person-ontology] first
>contributions - is the Higgins top-level useful?
>
>
>
>
>
>On 10/9/07, Paul Trevithick
><<mailto:paul at socialphysics.org>paul at socialphysics.org >
>wrote:
>
>If we just use a triple "Adam hasHairColor blonde" where blonde is a
>literal, we've no ability to make statements about the value "blonde". So
>what we do in Higgins is use two triples shown loosely here:
>
> Adam hasHairColor value1
> value1 value "blonde"
> value1 expires "Jan 1, 2010"
> value1 source "Dept of Motor Vehicles"
>
>Where "value1" is a subclass of Value (probably StringValue, to be precise).
>
>
>
>Naively, I wonder what you mean by value1 expires "Jan 1, 2010"
>does the blonde-ness of Adam's hair expire?
>
>If you mean that the hair color information is
>known to be good on Jan 1, 2010, good for you,
>but I find even that confusing.
>
>In general, this seems like some categorial
>error of talking about a value having an
>expiration date.
>The best I can assume from this snippet is that
>Adam's driver's license is expiring in Jan 1,
>2010
>which is totally different...
>
>David
>
>
>
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