Dublin Core is a set of definitions (semantics) for some common metadata elements. The fifteen unqualified Dublin Core elements are mapped to GILS by the Library of Congress Network Development and MARC (Machine Readable Cataloging) Standards Office (see ). Dublin Core does not specify syntax (although there is a W3C proposed convention for how to represent Dublin Core elements within HTML). These features of Dublin Core are in common with GILS. Unlike GILS, Dublin Core does not specify a search service. GILS-compliant search is being used very successfully in combination with Dublin Core semantics in operational implementations. See for a further discussion of the relationship between GILS and Dublin Core.