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Representation and a Proposal to WebOnt

by Peter F. Patel-Schneider


A formal view of representation languages has a number of useful consequences. These consequences are discussed in the context of a proposal for a web ontology language (OWL-1).

Presented at the first face-to-face meeting of the W3C Web Ontology Working Group, Murray Hill, New Jersey, January 2002.

What is a Representation Formalism?

Why are formal semantics needed?

Horror stories

Determining Meaning

Determining Meaning - Data models

Determining Meaning - Proof Theory

Determining Meaning - Model Theory

Determining Meaning - Axiomatization

Determining Meaning - Operational

Determining Meaning - Ideal Situation

Pitfalls in formal systems

Issues in the design of a Web Ontology Language

Relationships between (Representation) Formalisms

  1. semantic extension (only)
    • RDF and RDFS
  2. syntactic and semantic extension
    • propositional logic and predicate logic
  3. syntactic embedding
    • XML and RDF/XML

A simple Web Ontology Language (OWL-2)

Proposed Approaches


Proposed Approaches

OWL-1 (OWL) (4 January 2002)

Proposed Approaches

OWL-2 (OWL') (3 January 2002)

Problems with Proposed Approaches

Why is Entailment in DAML+OIL broken?

Why is Fixed Entailment in DAML+OIL problematic?

  • so no models are possible
  • paradoxes
  • Why is Entailment in OWL-1 difficult?