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Rules and the Semantic Web

Peter F. Patel-Schneider, pfps@research.bell-labs.com

Abstract

The Semantic Web is based on a "tower" of ever-more-powerful languages that allow computers to automatically represent and process the information needed to bring about this vision. Unfortunately, there are problems in the Semantic Web vision. These problems started with the properties of the various languages but currently have mostly to do with the placement of the various languages and the relationships between them. These problems started to show up with the development of the OWL Web Ontology Language but are even more severe when rules are added to the Semantic Web.

A basis for the Semantic Web that provides a problem-free place for rules and other even-more-powerful languages requires a fundamental revision of the way the Semantic Web is put together. One such basis involves separating the syntax of the Semantic Web from its semantics. In this way rules and other languages can easily be incorporated into the Semantic Web without the problems encountered in the past.

The Semantic Web

The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation. [Berners-Lee et al, 2001]

What is a Rule?

Condition [in Context] [produces Result]

Options for (Logic-like?) Rules

I am not really interested in the above options in this talk. Instead, I am interested on which kind(s) of rules fit into the Semantic Web and how they should be defined.

Old Semantic Web Architecture

Semantic Web Architecture

Problem with Old Architecture

Rules and the Semantic Web

Recent Semantic Web Architecture

Semantic Web Architecture (2005)

Rules as Part of the "Logic"

Rules as Part of the "Logic"

What remains?

A Proposal for Rules as Part of the "Logic"

Another Problem

Another Place for Rules in the Semantic Web

So what about Negation as Failure?

A Way Forward