reusing URIs vs. mapping with owl:equivalentClass

	Dear all,

	I have two related ontologies. One contains concepts represented in
multiple languages and with some relationships. The other covers only a
little part of this ontology, do not have all languages, but extend it with
many other related concepts. There are concepts that are the same in the two
ontologies. 

	Would it be better to reuse the URI of concepts in both ontologies or
should I assign new URIs to the second (more detailed) ontology and use the
equivalentClass construct?  What it be better?  For reasoning purposes what
it is better? How does the current reasoner such as Pellet or Racer process
owl:equivantClass? 

	Concerning maintenance, the first big ontology may be maintained, the
second one may be not.

	Thank you
	 
Best Regards,
Soonho Kim 

Knowledge and Information Consultant
WAICENT Knowledge Exchange Facilitation Branch (KCEW) 
Knowledge and Communication Department
Food and Agriculture Organization of the United Nation
Viale delle Terme di Caracalla
00100 Rome, Italy
Telephone: (+39) 06 5705 3409
Email: Soonho.Kim@fao.org