Note that Jena doesn't support N3 rules, I think this discussion is
about Jena Rules.
On 04/08/16 06:54, lookman sanni wrote:
Thanks Niels for the reply.
[AgeRule: (?person1 ex:person_Age ?age) (?person2 ex:person_Age ?age) ->
(?person1 ex:sameAge ?person2)] works fine for the purpose.
Now let's assume that person1 has two properties: sonAge and daughterAge
and I would like to infer a rule like person1 hasTwins. How would I write
it ?
You have to first decide how you want to represent the concept of having
twins. Then you write rules to implement that but your representation
must come first.
For example, if you decided to use a class for this (someone with twins
is a member of the class of people having twins) then you would write:
(?person eg:sonAge ?X) (?person eg:daughterAge ?X)
-> (?person rdf:type eg:HasTwins)
I'm not saying using classes is a good representation, just an example.
Dave
Thanks, Lookman
Le 4 août 2016 06:42, "Niels Andersen" <[email protected]> a écrit :
A general recommendation, please make sure that the properties that you
choose clearly describes the direction of the relationship. It is not clear
if ?f or ?a is the father.
There are probably a million opinions about how to do this, my general
recommendation is to create properties that show the class to the left and
the relationship to the right, so ?a ex:person_Father ?b would mean that
?a's father is ?b. It also makes it clear that the domain of
ex:person_Father is ex:Person and the range of ex:person_Father is
ex:Father.
Not sure if I understand your question, but you could do the following to
compare ages
[AgeRule: (?person1 ex:person_Age ?age) (?person2 ex:person_Age ?age) ->
(?person1 ex:sameAge ?person2)]
This rule would only trigger if both ?person1 and ?person2 are the same
age.
More specifically you could say:
[UncleRule: (?person experson_Father ?father) (?father ex:person_Brother
?uncle) -> (?person ex:person_Uncle ?uncle)]
[UncleAgeRule: (?person1 ex:person_Uncle ?person2) (?person1 ex:person_Age
?age) (?person2 ex:person_Age ?age) -> (?person1 ex:hasUncleWithSameAge
?person2)]
Not sure why you would do that, but it is just an example.
Niels
-----Original Message-----
From: lookman sanni [mailto:[email protected]]
Sent: Wednesday, August 3, 2016 20:37
To: [email protected]
Subject: Notation 3 Rule specification
Hi all,
I am beginning with Jena and I struggle with the specification of a rule
that would help infer new statements.
More concretely, I would like to know how to compare values of different
properties of a same resource in a rule file, following the n3 syntax.
E.g. [rule1: (?f pre:father ?a) (?u pre:brother ?f) -> (?u pre:uncle ?a)]
If we assume f and u have a property age and I would like to test whether
that property has the same value or not for both, how would I do it ?
Thanks, Lookman
