Re: New proposal for the semantics

To this particular point:

On 15/11/2021 15:47, Dörthe Arndt wrote:

>>> Ah, one additional remark: did you consider how we align with RDF?  >>> (...) > >> I believe that, for the subset of N3 graphs that are 
also RDF graphs, >> the proposed interpretations are effectively 
equivalent to Simple >> Interpretations... > > -> Now I see it. There is 
now slight difference for the handling of > blank nodes since we will 
have to find „witnesses“ for each blank > node (all instances of the 
universe the blank nodes point to will > need to have a name, even 
though we will never use that name > anywhere), but I think we would 
have to do that in all our solutions > because of the referential opacity.

Actually, only blank nodes used in quoted graphs need "witnesses".

This is illustrated at the bottom of p.6, although this example probably 
requires more explanation:

We assume here a form of D-entailment recognizing owl:real. This implies 
that any interpretation verifies:

* ℝ ⊆ Δ_I
* D_I(rdf:type) = T ∈ Δ_I,  D_I(owl:real) = R ∈ Δ_I
* { (x T R) | x ∈ ℝ } ⊆ EXT_I


Under such an interpretations, the following graph is always entailed:

   _:x a owl:real .

even though _:x has no "witness" in the interpretation.

best


>  > > Kind regards, Dörthe > > best > >> >> Kind regards and expect my 
follow-up mail :) Dörthe > > > >> >> >> >> >> >> ----- Weitergeleitete 
Nachricht ----- *Von:* Doerthe Arndt >> <doerthe_arndt@yahoo.de 
<mailto:doerthe_arndt@yahoo.de>> *An:* >> doerth.arndt@tu-dresden.de 
<mailto:doerth.arndt@tu-dresden.de> >> <doerth.arndt@tu-dresden.de 
<mailto:doerth.arndt@tu-dresden.de>> >> *Gesendet:* Montag, 15. November 
2021, 14:19:31 MEZ *Betreff:* Fw: >> New proposal for the semantics >> 
 >> >> >> ----- Weitergeleitete Nachricht ----- *Von:* Pierre-Antoine 
Champin >> <pierre-antoine.champin@ercim.eu >> 
<mailto:pierre-antoine.champin@ercim.eu>> *An:* Dörthe Arndt >> 
<doerthe.arndt@ugent.be <mailto:doerthe.arndt@ugent.be>>; Jos De >> Roo 
<josderoo@gmail.com <mailto:josderoo@gmail.com>> *CC:* >> 
public-n3-dev@w3.org <mailto:public-n3-dev@w3.org> >> 
<public-n3-dev@w3.org <mailto:public-n3-dev@w3.org>> *Gesendet:* >> 
Montag, 15. November 2021, 14:15:57 MEZ *Betreff:* Re: New proposal >> 
for the semantics >> >> More thoughts >> >> On 15/11/2021 13:32, 
Pierre-Antoine Champin wrote: >>> (...) >>> >>> More precisely, what we 
have is >>> >>> :markus a :penguin. :tweety :can :fly. { :tweety a 
:penguin } => >>> { :tweety :can :fly }. |= :markus a :penguin. ?x :can 
:fly. { ?x >>> a :penguin } => { ?x :can :fly }. >>> >>> From this, it 
would seem that we must infer that :markus :can >>> :fly. That would be 
a problem (as it is clearly not the intent of >>> the first graph), but 
the problem is actually elsewehere. There >>> exists a model of the 2nd 
graph (e.g. the Herbrand model of the >>> 1st one) in which :markus can 
not fly. So ":markus :can :fly" is >>> not entailed by the first graph 
(which is ok) but not entailed >>> either by the 2nd one either (which 
is a problem). So >>> rule-entailment actually fails to capture the 
semantics of rules >>> :-( >>> >>> Thanks for pointing that out. This is 
a bit frustrating, but >>> that's progress ;-) >>> >> My gut feeling is 
that this issue is causes by the merging of >> blank nodes and quick 
vars into a single kind of variables... >> Handling them differently 
might help solve this problem. I'll think >> about it. >> >> >> pa >> >