Syntax, Semantics and Knowledge

• A Web page wants to express some knowledge, using

• a presentation format (HTML, XSL...)

• a syntax with an intentional meaning (XML, DTD...)

• Speaking about a document

• comments, meta-tags, keywords

• RDF, Ontologies...

• Is it sufficient to be sure that a Web site or a document is semantically coherent ?

• Is it possible to give a formal semantics that express global constraints ?