From: Michael Kifer <kifer@cs.sunysb.edu>

Date: Thu, 08 Nov 2007 16:38:50 -0500

To: axel@polleres.net

Cc: "Public-Rif-Wg \(E-mail\)" <public-rif-wg@w3.org>

Message-ID: <30107.1194557930@cs.sunysb.edu>

Date: Thu, 08 Nov 2007 16:38:50 -0500

To: axel@polleres.net

Cc: "Public-Rif-Wg \(E-mail\)" <public-rif-wg@w3.org>

Message-ID: <30107.1194557930@cs.sunysb.edu>

Model theory of builtin predicates is not a problem. Modes (binding patterns) are extra-logical. We have to decide what do about them in terms of our recommendation (e.g., issue an error and abort). Builtin functions present a bigger challenge. They can also have fixed interpretation as functions, but builtin functions are partial, so they require special treatment in the model theory, and I am not sure if this complication is worth the trouble. --michael > Evaluable predicates: > > The most general definition of external predicates (built-ins), I know > of (in an attempt to write down the definition of Eiter et al. [1] in a > RIF suitable way): > > An evaluable predicate &pred(X_1,....,X_n) is assigned with one or more > binding patterns, where a binding pattern is a vector {in,out}^n. > Intuitively, an evaluable atom provides a way for deciding the truth > value of an output tuple depending on the extension of a set of input > predicates and terms. Note that this means that evaluable predicates, > unlike usual definitions of built-ins in logic programming, can not only > take constant parameters but also (extensions of) predicates as input. > inputs can not only be terms, but also predicate names (in which case > the *extension* of the respective predicate is the input.) External > predicates have a fixed interpretation assigned. 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, which can be computed by an external > evaluation oracle. > > > 1. T. Eiter, G. Ianni, R. Schindlauer, H. Tompits. A Uniform Integration > of Higher-Order Rea- > soning and External Evaluations in Answer Set Programming. In > International Joint Con- > ference on Artificial Intelligence (IJCAI) 2005, pp. 90–96, Edinburgh, > UK, Aug. 2005. > > > -- > Dr. Axel Polleres > email: axel@polleres.net url: http://www.polleres.net/ > > > > >Received on Thursday, 8 November 2007 21:39:09 GMT

*
This archive was generated by hypermail 2.2.0+W3C-0.50
: Tuesday, 2 June 2009 18:33:43 GMT
*