Thesaurus and Heading Lists: Equivalences and Divegences [chapter]

Pino Buizza
2020 Knowledge Organization at the Interface  
The variety of indexing systems needs interoperability to satisfy global information. In mapping projects and related literature, the focus is predominantly on equivalence relationships between terms. Starting from examples of terms mapped between the Thesaurus of Nuovo Soggettario and LCSH and Rameau, the semantic relationships of terms are explored to verify correspondences and divergences in related terms. The different structure of the examined vocabularies leads to semantic networks that
more » ... e not parallel. Specific and general remarks follow, in light of ISO 25964:2011-2013 and recent revisions. Aim and background The great variety of indexing systems, together with the use of different languages, meets the specific needs of their patrons. However, today access to information on a global scale requires interoperability, a theme widely studied, and mapping is the way to reach data coming from different sources. Many mapping tests have been carried out and a rich literature is available on the matter. 1 However, the focus is predominantly, if not exclusively, on equivalence relationships between concepts/terms. This attitude creates precise maps among single nuclei. However, it ignores the semantic relationships that are traditionally and diffusely represented in controlled vocabularies, hierarchical and associative relationships. Moreover, it loses sight of the overall correspondence of the envisaged systems. What happens if we explore their semantic networks? Do we find parallel or diverging nets? Do the correspondences go on step by step or stop at the starting points? This paper addresses this issue starting from mappings of the Thesaurus of Nuovo soggettario 2 (ThNS, source vocabulary) to Library of Congress Subject Headings 3 (LCSH) and to Repertoire d'autorité-matière encyclopédique et alphabétique unifié 4 (Rameau), as target vocabularies; all of them are characterized for general scope and produced by national bibliographic agencies. Some typical examples of mapping are reported, showing the equivalences and the most frequent divergences between the semantic networks and giving the starting point for justifying the divergences on the basis of the different features of the indexing languages or of their application criteria. The paper discusses some overall remarks on mappings and interoperability between different indexing languages and suggests possible alternative solutions drawn from ISO 25964:2011-2013, which is a sound reference to recognize and represent equivalences and their degree, to state meaningful and useful links where there is no equivalence, and to manage non-parallel systems. 1
doi:10.5771/9783956507762-59 fatcat:ghgy6vksebcrnjazbeqhlxpx6q