In building subject terms in authority file, one decision has to be made in dealing with compound subjects is precoordination vs postcoordination. In precoordinated system, the indexer or cataloguer predetermines the combination of topic terms to be used as index terms or headings. In postcoordinated system, the indexer or cataloguer uses single topic terms to be the index terms or headings. FAST is using the postcoordination approach as the syntax of the subject terms.
FAST uses the LCSH vocabularies because of the richness, being a well controlled system (e.g. synonym and homograph control; cross references), its compatibility with MARC. FAST keeps the semantic relationships in LSCH but simplifies its complicated syntax. The result is a set of vocabularies that is more applicable to Dublin Core, which is used by many digital library projects.
Title: Bank consolidation and small business lending: it’s not just bank size matters
Small business–United States–Finance.
Bank loans–United States
Topical: Small business–Finance
Geographic: United States
Title: Churches of Florence
Florence (Italy)–Buildings, structures, etc.
Florence (Italy)–Church history.
Topical: Church architecture
Buildings and structures
Form: Church history
(Source: Chan, Lois Mai. Cataloging and Classification: an Introduction. (3 ed.). Chapter 9)