- From: Michael Kifer <kifer@cs.sunysb.edu>
- Date: Mon, 15 Oct 2007 20:05:48 -0400
- To: Jos de Bruijn <debruijn@inf.unibz.it>
- Cc: public-rif-wg@w3.org
Just wanted to infuse a healthy doze of a reality check regarding the following: Jos wrote: > > >> g- the value space is required to be a subset of the ___domain. This > >> means that every interpretation includes all value spaces of all data > >> types. This is unnecessary. > > > > So what? It makes the definition simple and uniform. > > It makes every ___domain infinite. For most kinds of rules (especially > those without equality in the head) this is not really a problem. > However, as soon as we have full use of equality, or deal with > extensions in the direction of FOL, then one often wants to talk about > finite models. > > > It also makes rule sets which only contain rules such as Forall ?x,?y > (?x=?y) inconsistent. I claim that this is undesirable. Apart from everything that was said about it, you should remember that we have function symbols. So, the ___domain is infinite whether you have data types or not. --michael
Received on Tuesday, 16 October 2007 00:06:16 UTC