Re: [Core] binding patterns

On Wed, 13 Aug 2008 09:42:26 +0100
Axel Polleres <axel.polleres@deri.org> wrote:

> 
> Michael Kifer wrote:
> > As we discussed (a few months) earlier, binding patterns have no meaning
> > outside of a particular evaluation algorithm (procedural semantics). 
> 
> I remember well, but as long as this is not contradicting with the 
> existing semantics - I guess for core, we can kind of assume a standard 
> forward-chaining evaluation procedure, which only makes sense to me with 
> binding patterns and safety - I see no problem with this.

How did you "guessed" that? :-)
Why is it that in the core we can make such assumptions?

Furthermore, this makes sense only for some *particular* forward chaning
strategies and for particular backward chaining ones.


> > It is
> > therefore not clear how to incorporate them in the current spec, which is
> > supposed to be independent of the procedural things.
> 
> It would be only a part of the core dialect specification, which is just 
> a syntactic restriction of BLD with the exact same semantics as BLD.
> Would you see a problem with that?

I don't see  how this can be useful. If this is part of a spec then everybody
is supposed to implement it, no?
The core should be implemented by everyone, so I dont think this is good.

michael

> 
> Axel
> 
> > michael
> > 
> > On Tue, 12 Aug 2008 17:31:08 +0100
> > Axel Polleres <axel.polleres@deri.org> wrote:
> > 
> >> (put the subject under a [Core] label.)
> >>
> >> Binding patterns were mentioned a view times today, I thus try to 
> >> reformulate here a definition, which may be a helpful starting point 
> >> helpful in this context and which :
> >>
> >> An external predicate with external schema
> >>
> >>   ( X_1,....,X_n; pred(X_1,....,X_n) )
> >>
> >> is  assigned with one or more binding patterns, where a binding pattern 
> >> is a vector {in,out}^n:
> >>
> >> Any external predicate provides a way for deciding the truth value of an 
> >> output tuple depending on the extension of a set of input predicates and 
> >> terms. External predicates have a fixed interpretation assigned for 
> >> their intended domains. The distinction between input and output terms 
> >> is made in order to guarantee that whenever all input values of one of 
> >> the given binding patterns are bound to concrete values, the fixed 
> >> interpretation only allows a finite number of bindings for the output 
> >> values such that the predicate evaluates to true, and those finite set 
> >> of bindings which can be computed by an external evaluation oracle.
> >>
> >> If we agree to add something like binding patterns to DTB, I could start 
> >> to "collect" the possible binding patterns for the DTB predicates.
> >>
> >> Side remark: note that external functions don't need binding patterns 
> >> (obviously all parameters are 'in' and the only 'out' is the result.)
> >>
> >> Axel Polleres wrote:
> >>> Two pointers here... the notion of strong safety in hex-programs [1,2] 
> >>> and Topor's considerations on  safe database queries with arithmetics 
> >>> [3] (cudos jos for the latter one)
> >>>
> >>>
> >>> 1. R. Schindlauer. Answer-Set Programming for the Semantic Web. PhD 
> >>> thesis, Vienna University of Technology, Dec. 2006.
> >>> http://www.kr.tuwien.ac.at/staff/roman/papers/thesis.pdf
> >>>
> >>> 2.  Thomas Eiter, Giovambattista Ianni, Roman Schindlauer, and Hans 
> >>> Tompits. Effective Integration of Declarative Rules with External 
> >>> Evaluations for Semantic Web Reasoning. In York Sure and John Domingue, 
> >>> editors, Proceedings of the 3rd European Conference on Semantic Web 
> >>> (ESWC 2006), Budva, Montenegro, number 4011 in Lecture Notes in Computer 
> >>> Science (LNCS), pages 273-287. Springer, June 2006.
> >>> http://www.springerlink.com/content/f0x23wx142141v44/
> >>>
> >>> 3. R. Topor. Safe database queries with arithmetic relations (1991)
> >>> Proc. 14th Australian Computer Science Conf 
> >>> http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.48.4845
> >>>
> >>>
> >>
> 
>

Received on Wednesday, 13 August 2008 18:29:22 UTC