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8/11/2019 YOSHIO. on Nary Relations
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On Nary Relations
This documnent describes my ideas on the way to represent Nary Realtions in RDF.
Table of contents:
Nary Relations
Trinary Cases
Unary Cases
Binary Cases
Cuasal relathionship
Discussion on reification and uncertaintyOn patterns in the WD from SWBPDWG
Nary Relations
The basic relationship we can describe with RDF is binary, namely a relathionship between two resources.
However, there are many cases that we want to express the relationship among more than 2 resources. And therehave been discussions and proposals for the framework for the description of those Nary relathionships (see
NaryRelations page in ESW Wiki for example)
And RDF Best Practice and Deployment WG has published its working draft Defining N-ary Relations on the
Semantic Web: Use With Individuals.
This page presents my (ongoing) proposal for a framework for presenting N-ary relationships.
It looks similar to the "Pattern 2" analysis in the working note, but more generalized to include "unary" and "binary"
case, and basic vocabulary is proposed here(@@they appear in examples, but yet to be defined formally)
This approach owes its most part to the approaches in linguistics.
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Trinary Cases
Dative expression
Example:
John teaches math to Mary.
[ a :teach;
role:agent :John;
8/11/2019 YOSHIO. on Nary Relations
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role:thme :Math;
role:goal :Mary
].
Actually the analysis is the same as that of "John teaches Mary math."
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Unary Cases
Agentive subject
Example: "John swims."
[ a :swim;
role:agent John ].
Thematic subject
8/11/2019 YOSHIO. on Nary Relations
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Example:
"Titanic sank."
[ a :sank;
role:theme :Titanic ].
or
[ a :sink;
role:theme :Titanic;
role:tense role:past
].
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Binary Cases
8/11/2019 YOSHIO. on Nary Relations
http://slidepdf.com/reader/full/yoshio-on-nary-relations 4/12
By generalizing the "Predicate as the main node" approach above to the trinary and unary cases, we get somewhat
new (or unfamiliar) graphs for conventional binary relations.
Namely, even in expressing binary relationship, we make a node representing the (instance of) main predicate, and
connect each arguments to that node.
This approach is similar to reification, but different in that the "main" node is not of type rdf:Statement, but of the
seamantic predicate (so we don't have arcs labeled rdf:predicate) . And labels attatched to the arcs are not
syntax labels likerdf:subject or rdf:object, but semantic ones ( thematic roles aka θ roles).
Agent, Theme
Example:
John teaches math.
[ a :teach;
role:agent :John;
role:theme :Math].
Agent, Location
Example:
John swims in the pool.
[ a :swim;
role:agent :John;
role:location :Pool
].
8/11/2019 YOSHIO. on Nary Relations
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Or
[ a :swim;
role:agent :John; role:location [ a :in;
role:theme]
].
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Cuasal relationship
Something causes something
Let's begin with a very simple case.
Example:
Smoking causes lung cancer.
8/11/2019 YOSHIO. on Nary Relations
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[ a :cause;
role:source :smoking;
role:theme :lung_cancer
].
Something cuases someone to do something
Example:
John made Mary meet Sarah.
[ a :made; role:agent :John;
role:theme [ a :meet;
role:experiencer :Mary;
role:theme :Sarah
]
].
8/11/2019 YOSHIO. on Nary Relations
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Some event causes someone to do something
Example:
That John died made Mary refrain from smoking.
[ a :made;
role:source [a :died; role:theme :John];
role:theme [a :refrain_from;
role:agent :Mary;
role:source :smoking]
]
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Discussion on reification and uncertainty
What's the problem? an example and an analysis
When adopting analysis above, do we have any problems with reification?
When doing reification as usual, the resultant graph seems a little bit complicated.
For example, consider "John teaches math.", of which our analysis was
[ a :teach;
role:agent :John;
role:theme :Math
].
8/11/2019 YOSHIO. on Nary Relations
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When we apply reification to that graph, the result would be
_:b2 a rdf:Statement; rdf:subject _:b1;
rdf:predicate role:agent;
rdf:object :John.
_:b3 a rdf:Statement;
rdf:subject _:b1;
rdf:predicate role:theme;
rdf:object :Math.
_:b1 a :teach.
Does this seem problematic? → At first glance, yes. It's too much complicated.
However, the sentence above actually (simulutanously) says these two things:
It is John who teachs math.and
It is math that John teachs.
So, it is natural that we have two reified triples.
8/11/2019 YOSHIO. on Nary Relations
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And we can attach our belief to either of them. For example, we can say "It is 75% probable that it is John who
teaches math." with
_:b4 a prob:Belief;
prob:proposition _:b2;
prob:has_probability [a prob:probability;
rdf:value "0.75"].
Another analysis
Actually, there could be another analysis: a more complicated/sofisticated version. In the analysis above, we
didn't reify the statement ":b1 a rdf:type", but we can also reify it.
So, the reified version is:
_:b2 a rdf:Statement;
rdf:subject _:b1;
rdf:predicate role:agent; rdf:object :John.
_:b3 a rdf:Statement;
rdf:subject _:b1;
rdf:predicate role:theme;
rdf:object :Math.
_:b4 a rdf:Statement;
rdf:subject _:b1;
rdf:predicate rdf:type;
rdf:object :teach.
8/11/2019 YOSHIO. on Nary Relations
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What does this mean? It means "It is to teach (not to study, for example) that John does with math." (I'm not
sure if it's correct English senence, though)
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On patterns in the WD from SWBPDWG
Christine has breast tumor with high probability.
[ a prob:Belief;
prob:proposition [ a :have;
role:location :Christine;
role:theme [ a :breast_tumor]
];
prob:has_probability _:b1
].
_:b1[ a prob:probability].
_:b2[ a :high;
role:theme _:b1].
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Steve has temperature, which is high, but falling
[ a :have;
role:location :Steve;
role:theme _:b1
].
_:b1 a :temparature.
[ a :high;
role:theme _:b1
].
[ a :falling;
role:theme _:b1
].
John buys a "Lenny the Lion" book from book.example.com for $15 as abirthday gift.
[ a :buy;
role:agent :John;
role:theme [ a :Lenny_the_lion_book];
role:source :books_example_com;
role:instrument "$15";
role:purpose :birthday_gift
].
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Created by Yoshio Fukushige