Re: Syntactic Options for Probabilistic Semantics

Dear Adam,

I like your idea to express probabilistic semantics with N3, but I would like to clearly understand why you think that we need the @-based directives for it instead of using the language as it is together with a defined vocabulary. The background here is, that in the N3 group we try to avoid keys and special constructs where possible.  So, why would you need the special construct?



Brainstorming, we could, in a manner resembling other @-based directives in N3, express:

@p(0.95) . { domain:X domain:r domain:Y . }

Instead of writing that, you could also simply add some predicate :probability (of course using a shared vocabulary and not just something made up ad-hoc) and state:


{ domain:X domain:r domain:Y . } :probability 0.95.

The advantage of doing so is, that you would even be able to reason with your probabilities without any extra effort. If you have the probability of a person having black hair and the probability of a person being male

{:person a :Male} :probability 0.49.
{:person :hairColor :black } :probability 0.3.

You could use a rule to calculate the probably of encountering a male with black hair just like:

{
{?s ?p ?o} :probability ?x.
{?s ?p2 ?o2} :probability ?y.
{?s ?p ?o} log:notEqualTo {?s ?p2 ?o2}.
(?x ?y) math:product ?z.
({?s ?p ?o} {?s ?p2 ?o2}) log:conjunction ?c
}=>{
?c :probability ?z
}.

And get that

{:person :hairColor :black. :person a :Male} :probability 0.147 .

You can also directly try the example here: http://ppr.cs.dal.ca:3002/n3/editor/s/RfwLWp8T


I would of course expect, that the rules you would actually need for proper probabilistic semantics are far more complicated, but I also think that the built-ins in N3 would allow you to write some exchangeable rules supporting the theory. So, having these nice implementations at hand, I wonder why you would want to ask for extra syntax? You could stay in the syntax as it is and define a vocabulary (ontology, depending how far you go) for the concept of probability which we would then reuse.


Also, beyond [0, 1] scalars per fuzzy logic, there are multivalued logics, e.g., neutrosophic logics which describe every logical variable x as being described by a triple: x = (t, f, i), where t is the degree of truth, f is the degree of false, and i is the level of indeterminacy. We could express this in a manner resembling:

@p(t: 0.95, f: 0.05, i: 0.0) . { domain:X domain:r domain:Y . }

Would

{ domain:X domain:r domain:Y . } :probability_t 0.95, :probability_f 0.05, probability_i: 0.0.

also do the job? Why would you want to have the special format?



What do you think of these syntactic options for expressing probabilistic semantics in N3-based languages?

Before I form an opinion, I really need to understand, why we would need extra syntax here. I am sure, I am missing something, but so far, it looks to me that the proposal rather complicates the language than bringing extra advantages. Maybe an example could help?

Kind regards,
Dörthe