Re: Notation 3 Rule specification

[Dave Reynolds]

On 07/08/16 09:24, lookman sanni wrote:
Thank you Niels, you made my day with the notEqual() function. The built-in
primitives page that you suggested is a gold mine.
@Dave: Jena does support N3 rules

Only if you use an external rules engine and I'm not aware of one.

I can assure you that Jena's GenericRules engine, as documented at:

https://jena.apache.org/documentation/inference/#rules

does not support N3 rules. There is some superficial similarity in that 
they are forward chaining rules which allow triple patterns in both left 
and right hand side. However, aside from the syntactic differences, the 
set of builtins is quite different. JenaRules does not, and probably 
could not, usefully support the metaprogramming stuff in N3 
(log:semantics, log:parsedAsN3 etc). The approaches to integrity 
checking rules is quite different as well.

Dave

On Thu, Aug 4, 2016 at 8:06 PM, Niels Andersen <ni...@thinkiq.com> wrote:

Here is how I would do it:



[RuleMotherMutipleBirths: (?person rdf:Type ex:FemalePerson) (?parent
ex:person_Child ?Child1) (?parent ex:person_Child ?Child2)
notEqual(?Child1,?Child2) (?Child1 ex:person_Birthday ?ChildBirthday)
(?Child2 ex:person_ Birthday? ChildBirthday)

-> (?parent ex:person_ChildrenType ex:HasMultipleBirth) (?Child1
ex:sameBirth ?Child2) (?Child2 ex: sameBirth ?Child1)]



A couple of things to watch out for here:

·         This rule will cover any multi berth situation (twins, triplets,
etc)

·         The kids must come from the same birth, not just have the same
birthday or age. Therefore the parent must be a female.

·         The rule will not work if the twins are born on two different
days.

·         Not sure the word Birth is the right one, try to find a better
one.



Look at https://jena.apache.org/documentation/inference/#
builtin-primitives for inspiration.



Now you can write a rule that shows that a man has twins. I’ll leave that
for you to try.



Niels





-----Original Message-----

From: lookman sanni [mailto:lookous...@gmail.com]

Sent: Wednesday, August 3, 2016 22:55

To: users@jena.apache.org

Subject: RE: Notation 3 Rule specification



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 ?



Thanks, Lookman

Le 4 août 2016 06:42, "Niels Andersen" <ni...@thinkiq.com> 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:lookous...@gmail.com]

Sent: Wednesday, August 3, 2016 20:37

To: users@jena.apache.org

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