Warning: technical DwC whine I am attempting to use DwC in RDF to model something that is functionally like the predicate lsidvoc:identifiesTo in the LSID vocabularies. If I understand correctly, in DwC I must start with an \instance/ of dwc:ResourceRelationship, lets call it x:identifiesTo and use its dwc:resourceID to provide the source Identification and its dwc:relatedResourceID to provide the instance's object Taxon. The problem is, you can't use the same instance x:identifiesTo for two different (Identification, Taxon) pairs because you won't be able to tell which Identification goes with which Taxon. A little more precisely, if you don't have another instance of dwc:Resource Relationship, you will have: x:identifiesTo rdf:type dwc:ResourceRelationship x:identifiesTo dwc:resourceID Identification1 x:identifiesTo dwc:relatedResoruce Taxon1 x:identifiesTo dwc:resourceID identification2 x:identifiesTo dwc:relatedResourceID Taxon2 (This is a generic multiplicity problem about RDF vocabularies that mean to support flat implementation. In some context recently I made that observation on this list. If I were as careful as Steve B I'd go back to the record, find out where and cite it :-) . But I have to rush off and go collect a few weeds from my lawn and get off to a weekend course on botanical printing on fabric sponsored in part by the Arnold Arboretum !) Probably the only solution is to introduce a real predicate outside of DwC that actually looks like lsidvoc:identifiesTo so the graph looks like x:identifiesTo rdf:type rdfs:Property Identification1 x:identifiesTo Taxon1 Identification2 x:identifiesTo Taxon2 This is essentially the approach of http://code.google.com/p/darwin-sw/. Even this has some implementation issues in an environment where you are facing some RDF that has vocabulary from an ontology named by a URI that you can't resolve, which is what we are exploring in the FilteredPush project about the management of annotations of data. I'd love to be shown why I am wrong about the non-reusability of a dwc:ResourceRelation, or whether there is a different way to solve problems like this in DwC Bob Morris -- Robert A. Morris Emeritus Professor of Computer Science UMASS-Boston 100 Morrissey Blvd Boston, MA 02125-3390 IT Staff Filtered Push Project Department of Organismal and Evolutionary Biology Harvard University email: morris.bob@gmail.com web: http://efg.cs.umb.edu/ web: http://etaxonomy.org/mw/FilteredPush http://www.cs.umb.edu/~ram phone (+1) 857 222 7992 (mobile)