The really interesting thing, however, is to be able to describe relationships between topics, and for this the topic map standard provides a construct called the topic association. A topic association asserts a relationship between two or more topics. Examples might be as follows: “Tosca was written by Puccini” “Tosca takes place in Rome” “Puccini was born in Lucca” “Lucca is in Italy” “Puccini was influenced by Verdi”