having triples, how to annotate terms in page?

Hello,

I'm working on PowerMagpie [1], which is finding triples that can be
matched to terms in a web page (I'm maching labels, local names and
literals).

I would like to express the matchings in the page as RDFa, for example
for  "mad cow" somewhere in the page I have this matching class:

http://cohse.semanticweb.org/ontologies/people#mad+cow
which has label "mad cow"

How is the best way to express this triple in the page?

... <span about="http://cohse.semanticweb.org/ontologies/people#mad+cow"
instanceof="owl:Class" property="rdfs:label">mad cow</span> ...

should I be less (no instanceof) or more verbose?

The goal is to share at DOM level what PowerMagpie detects in a page
with any other RDFa aware extension (such as Operator).

[1] http://powermagpie.open.ac.uk/

Cheers,
-- 
Laurian Gridinoc
PhD Student, Knowledge Media Institute